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Magsimus Deluxe 6.0 user manual

1. 1197636199027 a Simulation Runin background En Pause Stoo b c Fig 3 1 Magsimus Deluxe user interface a Overview 1 tool bars of main program window 2 Design Manager 3 External field controls 4 System display pane 5 data windows 6 status bar b Close up of main program upper tool bar Recording and simulation 1 Record button 2 Forward play button 3 Reverse play button 4 Pause button 5 Stop button 6 Replay Go to button 7 Replay mode drop down list c Close up of main program lower tool bar system display 1 component lock unlock button 2 zoom full button 3 zoom box button 4 zoom last button 5 zoom out button 6 rotate button 7 perspective view button 8 undo button 9 redo button 10 show motion button 11 System view drop down list 12 On display drop down list Tutorial 1 Interacting objects Overview In this example you learn the following e How to create a design consisting of different types of components e How to specify the data outputs to be generated from a calculation or simulation How to define mechanical motions in a design How to run and record a simulation Fig 3 2 shows our first example in its completed form The design referred to as the system consists of several objects that are indicated by the numbers in the figure The numbe
2. Table 5 1 Mathematical symbols introduced in Chapter 5 Symbol Meaning H Pinning magnetic anisotropy field vector m Unit magnetization vector k Unit magnetic anisotropy easy axis vector K Magnetic anisotropy vector H Exchange coupling field magnitude V Volume Ho Permeability of free space W Energy density e Conductivity of component 6 Intrinsic conductivity of component Ao Change in conductivity of component Ac Maximum change in conductivity of component due max to GMR n Pre factor in expression for Ao a Current shunt factor AGMR GMR ratio H Spin momentum transfer effective field vector Mp Bohr magneton e Electronic charge I Electrical current magnitude A AMR AMR ratio F Force vector kp Boltzman s constant Phenomenological temperature coefficient Temperature Table 5 1 Mathematical symbols introduced in Chapter 5 Symbol Meaning Integration time step or characteristic thermal settling time V Volume of computational cell T Thermal pre factor used in equation 37 Chapter 6 Magsimus Reference Main program window Introduction The start up screen of Magsimus is shown in Fig 6 1 This screen consists of the main program window with caption Magsimus Deluxe Untitled mus and the System View Window that is contained in it The user will more often interact with these windows while usin
3. 34 l Use field definitions Leg 7 ef o Field Mode Single Scale De 100 H De z a Azimuth Deg 0 4 Polar Deg D 4 d gt Fig 3 7 System view window displaying all components of the first group Before proceeding further let us save the design we have so far To do this select the menu item File gt Save from the main program menu You are prompted for the name of the file to save the design to Enter a file name such as TestDesign or any other name of your choice and press Save The design has now been saved to the specified file If the entered file name has no extension it is saved with the default extension mus for example as TestDesign mus It is always a good idea to periodically save your designs After the design has been saved once selecting File gt Save again saves it to the previously entered file without prompting for a new file name To save the design to a different file select the File gt Save As item from the menu A saved design can be loaded into the program by selecting the File gt Open menu item Interacting with the group components The displayed elements can now be interactively manipulated in other ways We may elect for example to move an element to a new position or modify its size To move the element first select it then holding down the left mouse button move
4. Compute induced surface charges of shields Invoke solver Converged Fig 5 2 Computation algorithm illustrated by the flow chart of Fig 5 2 The solver prescribes how the magnetization vectors of the system are to be varied during each iteration The iteration concludes when the system attains an equilibrium magnetic state The following conditions are simultaneously satisfied at equilibrium 1 The magnetic torque per unit volume at all elements and arrays becomes less than some specified tolerance usually a small positive number 2 Therelative change of the magnetization vector magnitude between iterations for all pseudo soft magnetic components becomes everywhere less than the convergence tolerance 3 The relative change of the surface pole distributions between iterations of all shields becomes everywhere less than the convergence tolerance The relative surface pole density is computed with respect to the saturation magnetization of the shield Conditions 2 and 3 above ensure the self consistency of the computed magnitudes of the magnetization vectors of pseudo magnets and surface pole distributions of shields The equilibrium state is tested for stability by randomly perturbing it and continuing the calculation Stability is confirmed if the magnetic state re relaxes back to the equilibrium state within a specified angular tolerance Magsimus uses a separate solver for dynamic calculations and th
5. Anisotropic magnetoresistance AMR Giant magnetoresistance GMR Electrical circuits Nodal analysis of general linear networks Generic current sources Harmonic pulse train and complex current signals Easy to use point and click circuit design interface Electrical current distribution Computation of electrical current distribution among the cells of array components Vector maps of electrical current density fields Spin momentum transfer SMT effects Generic and flexible model for SMT effects in magnetic multilayers Magneto thermal effects Modeling of temperature dependence of magnetization and magnetic anisotropy Easy generation of virtually any thermal characterization of magnetic anisotropies Available interface for the easy specification of thermal sources and the application of virtually any temperature profile to components of a design Motion Independent translation and or rotary motion of components Complex motions generated from combination of simpler ones External fields Application of field to whole design and or selectively to individual components Field types Loops rotary fields pulse fields etc Complicated field variations obtained from combination of simpler ones Parametric simulation Sweeping of field and design component parameters Parametric data outputs Surface plots surface slices etc Recording of simulation Recording of time consuming simulations for later
6. Fig 7 11 System external field specification dialog An external field sequence to be applied to the system during a simulation is specified under this tab Fig 7 11 A sequence is a collection of field egs that could be of a variety of field types You can specify vector external field types that will act on all components of the system or that are restricted to the components of a particular design group This is accomplished by selecting the appropriate option System level or Group level in the Select field scope frame at the top of this dialog box This preferential application of fields is a powerful capability that can be used to tailor external field forms to individual parts of the whole design In modern non volatile microelec tronic MRAM and sensor design applications this capability can be used to easily realize the so called toggle device switching modes A data specification area the field editor in the External field specs tab is redrawn with the appropriate dialogs to allow editing for the field type selected for the system or group By chaining an arbitrary number of legs of different types vector fields of almost any complexity in magnitude and direction can be applied to the system The group level field definitions apply to the group selected in the Select group list Checking the box Display group s field panel will cause the display of a generally changing group level field vector of a group in a separate wi
7. Plot type frame The graph to be plotted in the plot window is specified here by the selection of the corresponding option Normal Integral Derivative X Fourier Spectrum Y Fourier Spectrum and Spectral Filter The Normal option plots the originally specified out put data for the component The other options create plots of the corresponding data transformations of the normal underlying data For a choice of X or Y Fourier Spectrum the actual Fourier component that will be plotted Real part Imaginary part Amplitude or Phase is selected from the Spectral data drop down list Upon selecting the Spectral Fil ter option clicking the Settings button displays a dialog box for editing the filter properties Axes attributes frame The x and y axes attributes are defined here The options Auto and Manual inthe Scaling type frame determine the nature of the scale extents of the axis The option Auto causes the axes to scale automatically such that the entire curve fits the un zoomed plot win dow The Manual option applies to the plot window manually entered scaling axes extents entered in the boxes Xmin Xmax Ymin Ymax The number of major and minor tic marks along the axes is specified in the frames Major tic marks andMinor tic marks Colors frame Colors are defined for various parts of the curve window Background and Foreground The foreground color refers to the color of the curve plot The actions in this frame apply to the curre
8. Dynamic precession factor Dynamic damping factor YG Gilbert precession factor ag Gilbert damping factor Gyromagnetic ratio Relative permeability Minimum length of a side of a component Unit normal vector to a surface Surface pole density Table 5 1 Mathematical symbols introduced in Chapter 5 Symbol Meaning M Saturation magnetization External applied field vector Magnetic anisotropy field vector Hy Magnetostatic interaction field vector H Exchange interaction field vector H Thermal fluctuation field vector H Current generated magnetic field vector Hp Self demagnetization field vector Hs Inter element magnetostatic interaction field vector H Magnetic field vector of field produced by shield sources N Self demagnetizing tensor of element or array cell D Inter element magnetostatic interaction tensor Days Dyu etc Components of tensor D Ng Number of shield components in system S Surface area integration variable G Green s function Current generated volume averaged magnetic field hy of the k th current segment belonging to the j th i source component h Current generated magnetic field contribution of a current segment r Unit vector in direction of radius vector R Radius vector N Number of defined magnetic anisotropies for a g component H Uniaxial magnetic anisotropy field vector
9. Orientation of easy axis within element frame 46 in Magnetic Anisotropy tab of Array specification dialog 185 Oti J O 84 96 97 Outline and Current density vector arrow options in Lines and Colors tab of magnetic shield specification dialog box 202 output options in Electrical contact properties dialog box 177 Output current axis in Electrical contact properties dialog box 177 Output current axis list in Electromagnetic tab of Array specification dialog 183 Outputs 230 P panel 73 panels of electrical contact leads 176 Parameter Z box in parametric output window 214 Parameter category list 47 Parameter category option in Parametric simulation tab 152 Parameters area in Parametric simulation tab 153 Parameters frame 48 Parametric output window 213 Parametric plot box 48 in parametric output window 214 Parametric plot check box 48 Parametric plot window 208 Parametric simulation 230 Parametric Simulation specs tab 152 Parametric simulation specs tab 47 Pattern array System display pane action menu 145 Pattern array menu in integrated Design Manager 136 Patterning of arrays 203 patterning of arrays 114 Pause button in main program upper toolbar 109 in parametric output window 215 in Simulation area of main program s upper toolbar 110 permanent license 13 Permanent magnet 60 183 permanent magnet 18 19 228 permeability 63 personal computer PC 7 Perspective style Sy
10. 2 Probe holder Geometry Motion Data Output Electrical Circuit Motion Leg No 1 vl of 2 Return group to this leg s initial position after it terminates EO Eao Number of Motion Steps 20 Ceara NM Translation velocity in system frame Azimuthal Dea 0 PoarDeg4 nD Azimuthal 0 Polar 18 Magnitude nm steps Angular velocities of rotation Deg Step Cancel Help Fig 8 3 Motion tab of the Group specification dialog A very powerful feature of Magsimus is its ability to easily define mechanical motions for the components making up a design The defined motion may be a simple rotation through an angle a simple translation along a straight line or it may be a much more complex combination of rotations and translations Motions are defined for groups The group moves as one whole with its coordinate frame The motion for a group is defined in the Motion tab of its properties specification window shown in Fig 8 3 A motion definition is made up of an arbitrary number of defined motion egs Each leg defines a rotation and or translation motion of the group Complex motions are achieved by chaining simple motion legs The motion defined for a group can be viewed prior to a simulation by clicking the Show Motion button in the System display main program tool bar for more details see the topic Lower tool bar of main program window System display tool bar in Chapter 7 The motion leg are traversed
11. INMOGUCHON x arre e etra t RET pat ER UR RR ae hia on wate dnd Ren 161 Specifying the properties of the system object 000002 ee eee 161 Generaltab csse essi Bad BAL RR RR REA ek RR PAAR 162 Calculation tab iux sags Rm eee Ae ee a edhe eee ayaa UG REERRQ 163 Electrical Circuit tab i 2 ca cede eb ea pU RA 167 UES tabis MDC E TET 169 Group Specification dialog box 00 00 cee 170 Geometry tab sac liebe tae eG ARR eed ee ee eae ea 170 Electrical Circuit tab 2 0 eee 171 Specifying Motion 0 eae 174 Specifying electrical contacts for arrays 2 000s 176 About displaying component specification dialog boxes 179 Element and Array Specification dialog boxes 0 000 ee 180 Geometry tab fie ace ea ee ohare aw ie Yee ea ieee ee dae eh 180 Electromagnetic tab lisse 182 Magnetic Anisotropy tab 1 0 eae 184 Exchange Coupling tab 0 0 0 ccc tees 186 Magnetoresistance tab 0 0 eee 188 Lines and Colors tab s dkar aAa eee 190 Calculation Control tab 6 eee 192 User defined Parameters tab 0 0 0 0 ccc ee 194 SUMU sources tab sube suben Re eee p ROG ee dde eee 194 Probe Specification dialog box 2 0 cee ee eae 196 Geometry tab o csc a ee cee ae 196 Lines and Colors tab 0 0 eee 197 Magnetic Shield specification dialog box 00 0c ec ee 197 Electromagnetic tab 1 0 0 iaraa ia a A T E a E
12. and the Run button will become re enabled Recording the simulation Let us run the simulation again but this time we will record it The ability to record is particularly useful for later rapid replay and analysis of lengthy simulations that may be very time consuming to run over and over again The evolution of the magnetization geometry internal fields and data outputs of the system are stored as part of the recording The recording of a simulation is carried out using the main program Recording and Simulation tool bar Fig 3 13 Press the Rec Record button Its caption changes to Can the Cancel caption now printed in black from its former red color We are now ready to record a simulation Press the Run Simulation button to repeat the simulation At the end of the simulation the caption of the record button reverts back to Rec and the Forward play button becomes enabled Pressing the Forward play button replays the saved simulation Use the Reverse play button to play the recording backwards If the design is now saved to a file the recorded information is saved as well The recording can be replayed by loading in the file Refer to the online help for a full description of recording controls Summary The foregoing example illustrates these typical steps for creating and simulating a Magsimus design Step 1 Add components to the design as needed specifying their geometric and electromagnetic properties and
13. 20 In the frame Orientation of easy axis within element Deg enter Azimuth 0 Polar 90 2 Data Output tab Create one data output definition with following specifications X Axis System external field amplitude HextA from External field data category Y Axis Magnetization along external field Mh from Magnetization data category When you have finished entering the data press the OK button to close the Element specification dialog box In the Design Manager change the name of the element to Magnetic cube Right click the mouse anywhere in the System view pane and from the displayed floating menu select Set system display attri butes gt Show Magnetic Anisotropy Axes to have the anisotropy easy axis displayed in the system display pane this is a double ended arrow oriented in the direction of the defined anisotropy In the External Field Controls frame check the Use field definitions box and then click the Edit button next to it In the displayed simulation specification dialog enter the inputs 1 External field specs tab Create one field leg by pressing the Add button Select Loop in the Field Type drop down list Enter the following inputs Min field Oe 100 Max field 0e 100 Polar angle Deg 0 Azimuth angle Deg 0 No of data points 100 2 Parametric simulation specs tab Check the Generate parametric data box This flags that a parametric simulation is to be carried out In the
14. Motion display is paused paused by the user Message Meaning Motion display terminated by user The current display of defined motions was terminated by the user Playing recordings backwards in Auto mode A recorded simulation is being played back in the reverse order of the simulation using the Auto playback mode Playing recordings backwards in Auto Repeat mode Playing recordings forward in Auto mode A recorded simulation is being played back in the reverse order of the simulation using the Auto Repeat playback mode A recorded simulation is being played back in the normal order of the simulation using the Auto playback mode Playing recordings forward in Auto Repeat mode A recorded simulation is being played back in the normal order of the simulation using the Auto Repeat playback mode Ready The solver is currently idle and is ready for the next simulation Recording playback is paused The playback of a recorded simulation is currently paused by the user Recording playback terminated by user The playback of a recorded simulation was terminated by user Simulation is paused An ongoing simulation calculation was paused by the user Simulation is running The program is currently processing a simulation Simulation terminated by user An ongoing simulation was terminated by the user Submiting background jobs Please wait Magsim
15. Numerical Recipies Cambridge University Press Cambridge 1986 Chapter 15 Slonczewski J C Current driven excitation of magnetic multilayers J Magn Magn Mater 159 L1 L7 1996 Tsang C and S K Decker Study of domain formation in small Permalloy magnetoresistive elements J Appl Phys vol 53 2602 1982 Tsiantos V Scholz W Suess D Schrefl T and Fidler J The effect of the cell size in Langevin micromagnetic simulations J Magn and Magn Mat vol 242 245 2 999 2002 White R L Giant magnetoresistance A primer JEEE Trans Magn vol 28 2482 1992 Tunnel Junction Wikipedia http en wikipedia org wiki Tunnel junction 2012 Zhu J G and H N Bertram Magnetization reversal in CoCr perpen dicular thin films J Appl Phys vol 66 1291 1989 Glossary of mathematical symbols Table 5 1 Mathematical symbols introduced in Chapter 5 Symbol Meaning Time variable Rise time of pulse train signal max Duration time of pulse train signal Maximum current level of pulse train signal min Minimum current level of pulse train signal Amplitude of n th harmonic component of current Wave number of harmonic component of current Fundamental period of harmonic component of current n Initial phase of n th harmonic of current Generic magnetization vector Tz Generic magnetic field vector
16. field data category Y Axis Magnetization along external field Mh from Magne tization data category Exit the array specification dialog by pressing the OK button In the Design Manager change the array name to Array of 4 magnetic cells Remarks We created a group consisting of a 2x 1 x 2 array of normal magnet cells The cells of the array are non touching During a simulation the magnetization curve of the array as a function of applied external field will be plotted Group 4 Data inputs in Group specification dialog Geometry tab In the frame Group origin in system coordinate frame nm make sure that the option Relative to previous group is selected inthe Input type box then enter x 0 0 Z 800 Exit the group specification dialog by pressing the OK button Change the group name to Biasing field source Create an element component Data inputs in Element specification dialog Geometry tab In the frame Linear dimensions along coordinate axes nm enter Length Lu 1000 Width Lv 1000 Thickness Lw 500 Electromagnetic tab Magnet type Select Permanent magnet from drop down list In the frame Vector orientation Deg enter Azimuth 50 Polar 50 Exit the element specification dialog by pressing the OK button Change the element name to Moving permanent magnet in the Design Manager Remarks We created a group consisting of a permanent magnet which as the name suggests
17. for editing the color wheel for an array that is selected in the system display pane This dialog box is described in the section Editing Color Wheels below Set M color wheel scaling Displays a submenu for specifying the scale limits of the array color wheel Absolute Sets the color wheel scale limits to plus and minus of the satura tion magnetization value of the array Relative Sets the color wheel scale limits to the actual maximum and min imum values of the represented array color guide values M vector field color guide applies to arrays only Displays a submenu None Mu Mv Mw M amplitude that allows the specifi cation of the component of the array magnetization vector field on which the coloring of magnetization vector arrows are based when they are drawn The used color gradation is represented by the array color wheel see above This color gradation is not used when the submenu item None is selected In this case all magnetization vectors of the array are drawn in the same color Pattern array applies to arrays only Displays a dialog box for patterning an array This dialog box is described below in the section Patterning arrays Perspective style Displays a submenu that allows the specifi cation of the the style of projection Cabinet Cavalier Planar of the design on the system display pane This submenu also has a Settings item selecting it displays a dialog box for specifying the projection angle
18. velocity angle in Motion tab of the Group specification dialog 175 polarization term in SMT formular 88 polarized electrical currents 189 popup menus Design Manager 134 Portable Document Format PDF 13 Positive Infinity option Relative permeability in Electromagnetic tab of Array specification dialog 184 precess 71 precession 71 72 precession factor 71 pre factor 85 Pre Factor box Coupling term in Magnetoresistance tab of Array specification dialog 190 Preserve array layout patterns between specs edits option in General Option tab dialog of Environmental Settings dialog 114 Press W H 72 97 Print Floating menu in parametric output window 214 Print design Main program menu item 106 probe 7 Probe Specification dialog Geometry tab 196 Lines and Colors tab 197 Probe Specification dialog box 196 Probe specification dialog box 30 process identification number 126 productivity tools 51 profile pattern 67 Program Group 12 pseudo soft 68 Pseudo Soft magnet 182 Pseudo soft magnet 60 pseudo soft magnet 19 72 228 Pulse external field 157 pulse fields 230 Pulse train 229 pulse train 37 66 67 194 Purchase license agreement for long duration licenses 242 Purchase license agreement for Pay per use licenses 239 Q Quasi static in Calculation tab dialog of System specification dialog 164 quasi static 69 70 228 quasi static calculations 66 quasi static conditions 8 quasi static solv
19. 1 Open new Carousel button 2 Save Carousel button 3 Skip forward button 4 Play button 5 Skip backwards button 6 Add item button 7 Delete item button 8 Options button 9 Help button 10 Area in which design files that are part of the carousel are listed We will now load in the patterned media carousel First begin a new design by re starting Magsimus or by selecting the main program menu item File gt New Problem From the main program menu select the Special gt Recording Playback Carousel This displays the carousel window shown in Fig 3 16 Click the Open new Carousel button and in the displayed Open dialog box navigate to the appli cation s Examples directory and open the file PatternedMediaEx ample crsl Fig 3 17 The loaded carousel consists of two files WritingDots and ReadingDots representing previously recorded simulations of the writing and reading of the same patterned magnetic media Make sure that the Repeat a11 box is checked in the Carousel window and then click the Play button to start playing back the Carousel The first file is loaded and played back and then the second file is loaded and played back This play back sequence is repeated over and over again The play back can be paused or halted at anytime by means of the Pause or Stop buttons of the Simulation Controls area of the System view window Load in and play back the miscellaneous examples carousel Un checking the Repeat all box ca
20. 144 Edit menu in integrated Design Manager 135 Effective fields 69 74 Electrical Circuit group input 168 Electrical circuit 7 65 group output 168 Electrical Circuit tab 35 Electrical Circuits 108 electrical contacts 173 176 electrical current 230 Electrical current and voltage ouput of 84 Electrical current axis in Electrical contact properties dialog box 177 Electrical current source 17 Electrical display attributes for component area in Electrical contact properties dialog box 177 Electrical properties of array 62 of elements 59 63 Electromagnetic tab 23 25 33 element 227 Element and Array Specification dialog boxes 180 Element and Array Specification dialogs Calculation Control tab 192 Electromagnetic tab 182 Exchange Coupling tab 186 Geometry 180 Lines and Colors tab 190 Magnetic Anisotropy tab 184 Magnetoresistance tab 188 Stimuli sources tab 194 User defined Parameters tab 194 Element button in the System Design Manager 22 Element option 47 Element outline option 24 Element specification dialog box 25 33 Element Specification window 22 emu cc electromagnetic unit per cubic centimeter 20 Enable check pointing box in Calculation tab dialog of System specification dialog 166 Enable end of simulation geometric reset for new designs option in General Option tab dialog of Environmental Settings dialog 114 Enable geometry locking for new designs option in General Option tab dialog of Environment
21. 183 Vector map floating menu displayed in the System Display pane 216 vector maps 227 Vector orientation frame 33 Vector plot System display pane action menu 145 Vector tip angle in Lines and Colors tab of Array specification dialog 191 Vertical box in Moving Component dialog box 160 Vetterling W T 97 View list in main program lower toolbar 148 Voltage list in Start up Units tab dialog of Environmental Settings dialog 117 voltage sources 91 voltages 230 W W origin in Geometric tab of Array specification dialog 181 Origin in Geometric tab of Magnetic Shield specification dialog 198 Origin in Geometric tab of Probe specification dialog 196 W box 25 31 Warn user about presence of recorded data before deleting it check box in General tab dialog of System specification dialog 163 wave number 68 Web installation 12 White R L 84 97 Width Lv box 23 32 33 array size in Geometric tab of Array specification dialog 181 array size in Geometric tab of Magnetic Shield specification dialog 199 Wikipedia 68 Windows 2000 11 Windows 95 11 Windows 98 11 Windows NT 4 0 11 Windows XP 11 Write simulation recording data to external file check box in Calculation tab dialog of System specification dialog 166 X X input in Geometry tab of Group specification dialog 171 X and Y Fourier spectra as output curve data transformation 82 X Axis list 31 32 X box 30 31 33 X Fourier Spectrum plot type optio
22. 199 Calculation Control tab 1 nee 201 Lines and Colors tab 0 0c eee 202 Patterning of arrays 2 02 te eee eens 203 Data output dialog box 1 eae 206 Data output WindOWS 00002 eee 208 2 D Plot WINdOW 03 5 a0 daa be ha au ed vue aes POE oe ee a x IRR E dae 208 Plot settings dialog DOX 1 1 eee 211 Parametric output window 0 0000 213 2 D Vector Map window 2 0000 e eee eee 215 Magnetic shield charge MapS 0 0 0 cee 218 Materials library llis RR 220 Specifying electrical current signals llis 221 Pulse tralfi m ec aea Veet DR a aa Wa ADEL CALOR aaa V CE A 223 ARMONICSs vies PPT EUITTT 223 Importing components 00 c eee eee eee 224 Appendix A Magsimus features ata glance 227 Appendix B Data output categories 233 Appendix C Magsimus files eeeeeeeeeeeese 237 Magsimus LICENSE onc dcccc ccc RR RR RRR ERA REEL RR RRERRRRE E 239 Introdtctlori seapea a Recte crie RR OI d Re RR ad eal RR ode CR Reti 239 Purchase license agreement for Pay per use licenses 2 239 Purchase license agreement for long duration licenses 2000e eae Demonstration Evaluation license agreement 0 000 eee eee MagOasis Hard key Policy 0 00000 cece tees Chapter 1 Introduction Welcome to the world of Magsimus Deluxe the most comprehensive gen
23. 61 of elements 60 magnetoresistance 230 Magnetostatic 69 magnetostatic 75 Magnetostatic interaction field 75 magnetostatic interaction field 75 magnetostatic interaction tensor 76 magnetostatic interactions 8 Magnetostatic Principles in Ferromagnetism 96 magnetostatic truncation region 77 Magnetostatic truncation tolerance in Calculation Control tab of Array specification dialog 193 magnetostatic truncation tolerance 77 Magnetostatic truncation tolerance box in Calculation Controls tab of Magnetic Shield specification dialog box 201 Magnetostatics 228 Magnitude box 39 40 in External Field Controls 138 in Motion tab of the Group specification dialog 175 Magsimus licensing 13 14 Magsimus status bar 111 Magsimus User Extensions 108 Main progam menus File 105 Help 107 Special 106 Main program window 104 Main toolbar and System view colors areas in Color attributes tab dialog of Environment Settings dialog 118 Major tic marks frame in Plot settings dialog box 212 Make this a tunnel junction box in Electromagnetic tab of Array specification dialog 183 Mallinson J C 96 Manual axis attribute in Plot settings dialog box 212 Manual playback mode 230 Manually moving group and components precisely 160 Marker size input box in Plot settings dialog box 213 Marker symbol input box in Plot settings dialog box 213 Matdb ddd material library file 238 Material box in Electromagnetic tab of Array specificat
24. G 0 v 0 w 1000 Data Output tab Create one data output definition with following specifications X Axis Iterations from General data category Y Axis Y component electrical current field Hley from Electrical data category Exit the probe specification dialog by pressing the OK button In the Design Manager change the probe name to Field probe Remarks We created a group consisting of a probe object During a simulation the probe will sense the y component of the magnetic field generated by currents flowing in the design This will be plotted as a function of calculation iterations Group 3 Data inputs in Group specification dialog Geometry tab In the frame Group origin in system coordinate frame nm make sure that the option Relative to previous group is selected in the Input type box then enter 500 Y 0 Z 500 Exit the group specification dialog by pressing the OK button Change the group name to Array group Create an array component Data inputs in Array specification dialog Geometry tab In the frame Size of array cell nm enter Length Lu 500 Width Lv 100 Thickness Lw 500 In the frame Spacing between cells nm enter Along u 50 Along v 50 Along w 50 In the frame Array grid dimensions enter Along u 2 Along v 1 Along w 2 Data Output tab Create one data output definition with following specifications X Axis System external field amplitude HextA from External
25. Selecting an item in this box lists its possible outputs in the Data type box Select Electrical from the Data Category box then select the item Current I in the data type box Make this the Y output by pressing the button located directly above the Y Axis list this button bears a wide arrow that points downwards This data is the electrical current flowing through the element Specifying the Y data can also be accomplished by double clicking the data in the Data type box X data output is similarly specified by selecting an item in the Data type box and pressing the button located above the X Axis list We skip this step since the teration we intend for this part of the tutorial was already defined by default Additional data sets may be specified for the element in this way Refer to the online help for a full description of the Data Output tab f Element Specification 1 2 New Element2 Electromagnetic Geometry Magnetic Anisotropy Exchange Coupling Lines and Colors Calculation Control User defined Params Data Output Data type Options Magnetostatic X Generate output Voltage V Total fields Conductivity Cond Magnetoresistance X Generate graph u component electrical current field HleU 5 v component electrical current field Hlev Magnetic Force Generate transient output w component electrical current field Hlew Thermal User defined Y Axis POL GE Delete Clear l o Set output curve lines and colors S
26. The dialog boxes for arrays and elements are similar In this section we discuss only the array speci fication dialog box pointing out when necessary how it differs from those of an element The differences in the interpretation of some physical quantities for both kinds of primitives will also be pointed out Related input fields are organized as tabbed dialogs Figs 8 6a g All tabs except the Data Output tab will be described here The discussion of data outputs is treated later on in the chapter under the section Data output dialogs Geometry tab fl Array Specification 1 3 Array of 4 magnetic cells Lines and Colors i User defined Params Data Output Stimuli sources Electromagnetic i j Magnetic Anisotropy Exchange Coupling Magnetoresistance Component origin in group coordinate frame nm Input type Relative to the previous component Angular orientation coordinates within group Deg u fo Azimuthal 0 V i Polar 0 Ww 0 Size of array cell nm Spacing between cells nm Array grid dimensions Length Lu po Along u Bo Alongu 2 WidthLy 100 EOS Along 1 Thickness Lw pn Along w p Along w amm Cancel Help Fig 8 6a Geometric tab of Array specification dialog box The coordinate origin the linear dimensions and the angular orientations within the parent group of the array is defined here Fig 8 6a See Chapter 4 for additional information on the coordinate
27. The drop down list at the top of this area contains the connectable components of the group Selecting a component from this list defines it as a source component An icon appropriate for the type of selected component is displayed to the right of this list Direction of current Specifies the source component axis u v or w along which current will flow in the component Use as group input Selects or de selects the source component as the group input component to be used while connecting the group circuit to the system electrical circuit Edit elect contacts applicable only when an array is selected as a source component Pressing this button displays a dialog box for specifying the electrical contacts of the source component This dialog box is described under the topic Specifying electrical contacts below Use as group output Selects or de selects the source component as the group output component to be used while connecting the group circuit to the system electrical circuit Current source area The type of current sources connected to a source component are specified in this area A current source has two terminals positive and negative The positive terminal is connected to the positive terminal of the source component while negative terminal can be connected to the negative terminal of the source component or another circuit component None Specifies that a current source is not connected to the source compo nent Constant cu
28. V Conductivity Cond u component electrical current field HleU v component electrical current field HleV w component electrical current field HleW Electrical u component magnetic force FU v component magnetic force FV w component magnetic force FW X component magnetic force FX Y component magnetic force FY Z component magnetic force FZ Magnetic Force Table 1 3 Data output Categories for a probe Data Category Data Type Distance General Iterations Time X component of magnetization Mx Y component of magnetization My Z component of magnetization Mz Magnetization along external field Mh Magnetization Magnetization magnitude M X component of magnetic induction Bx Y component of magnetic induction By Z component of magnetic induction Bz Magnetic induction along external field Bh X component of external field HextX Y component of external field HextY Z component of external field HextZ External field magnitude Hext System external field amplitude HextA External field energy density Wext External field X component of anisotropy field Hanix Y component of anisotropy field HaniY Magnetic anisotropy Z component of anisotropy field HaniZ Anisotropy field magnitude Hani Anisotropy energy density Wani X component of exchange field HexcX Y component of exchange field HexcY Exchange Z component of exchange field HexcZ Exchange field magnitude Hexc Exchange energy densi
29. Y Z or X Z in the frame below the Parametric plot box Use the slider to vary the position of the cutting plane or enter a value in the box to the right of the slider fel 171 Y vs X Magnetization along external field Mh emu cc Vs System external field a E3 Stato Parameter 2 FORSTER Eneo Curent bo Cut trace Z vs X Parametric plot 16 5 12 4 8 2 Ti F mG Current scan trace Scan 6 of 10 Y vs X Next Scan Cancel CxvY CY Z X Z simulation i Ua 3 Pase Fig 3 15 Parametric output window Recording Playback Carousels Magsimus provides a Recording Playback Carousel feature which is powerful for collating and playing back several recorded simulations at once Carousels are saved in special carousel files which have the default file extensions crsl Two sample carousels are included with your Magsimus installation These carousels have the file names PatternedMediaExamples crsl and MiscExamples crsl They represent respectively the reading and writing processes in patterned magnetic media and a collection of miscella neous design samples These carousels are stored in the application s Examples directory You can also create your own carousels for playing back related recordings of your future projects Repeat all Randomize playback sequence Fig 3 16 Recording playback carousel window The numbered components of the window are
30. a new license file from MagOasis Magsimus licenses allow the user to run an arbitrary number of instances of the program on one computer workstation Allowed session counts are specified for the license types requiring the use of internet connections The session counts determine the maximum number of workstations in which Magsimus can run simul taneously under the license Soft key license Soft key licenses are enforced over the internet using MagOasis Remote Licensing System The computer on which Magsimus is installed must be connected to the global Internet for this license to work properly Note The Remote Licensing System RLS does not interfere with the normal operations of corporate intranets Certain network firewall configurations may however interfere with the RLS Contact your system administrator to resolve such issues Hard Key license For this form of license MagOasis provides a Hardware key and a license file The hardware key must be connected to a USB port of the computer for the license to work properly Chapter 3 Tutorials This chapter is intended to acquaint the newcomer to Magsimus with the workings of the software We begin with an overview of the user interface This is followed by a step by step walk through of two tutorials that illustrates the creation of Magsimus designs We conclude with a discussion of a variety of Magsimus productivity tools We recommend that a new user review the tutori
31. an item on this box displays a message of its full path name Other controls Runjobs in background Checking this box causes the all the jobs to be submitted as background jobs when the Run button is pressed Create a recording carousel Pressing this button creates a recording playback carousel corresponding to the batch job definition Background jobs Simulations can be carried out in Magsimus as foreground or background jobs For a foreground job the simulation runs inside the Magsimus user environment This enables the user to observe the simulation directly as it executes A background job on the other hand is submitted as a separate process that runs independently of the loaded application After submitting a background job the user can continue working on new designs in Magsimus Background submission is ideal for large problem sizes and other jobs that may take a very long time to complete In such cases it may be convenient to relegate them to the background Background simulations can be submitted singly or in batches To submit a single background job first check the Run in background box of the Simulation area in the program upper tool bar before running the simulation Batch background simulations are submitted from the Batch Job Manager see above by first checking the Run jobs in background box before submitting the batch job Each background job is characterised by a process identification PID number assigned by the
32. and sizes The careful choice of the dimensions and properties of the components of the groups permits the modeling of a wide range of technologically interesting and useful systems The software uses an ordinal numbering scheme starting with 1 to identify elements and groups Groups can move in space The motion of a group entails the movement of all its constituent components according to a defined motion The components of a group may be electrically connected together to form a group electrical circuit Group electrical circuits may be combined to form system electrical circuits 4 b Fig 4 2 An array element and probe on display at the system display pane Coordinate system Several Cartesian coordinate systems are defined for the system being modeled These are 1 system problem coordinates XYZ 2 group coordinates UVW 3 group component coordinates uvw The coordinate system XYZ is fixed in space and has its origin at the point 0 0 0 The group coordinate systems UVW are defined relative to the problem coordinate system by specifying the displacement and orien tation of the group The displacement of the group coordinate system may be relative to the group occupying the prior position in the system if such a group exists or it may be relatve to the system origin The user is offered the option of specifying which input type is intended The angular orientation of the group is relative to the syst
33. array can be specified to exhibit macrospin behavior This results in it being always uniformly magnetized with the magnetization of all cells rotating in unison Thus the array always exhibits single domain behavior Self intra layer exchange interaction plays no role in the calculations the array responds to the volume average over it of the other interaction field terms Magnetic shield Geometric properties A magnetic shield shares the same shape coordinate system definition and geometric characteristics with an element as described above Electrical properties A shield just like an element is characterized by an electrical conduc tivity and electrical current can flow through it in a direction that is parallel to one of its coordinate axes Current is assumed to flow uniformly in the shield Magnetic properties A shield is characterized by a saturation magnetization and relative permeability An ideal shield has an infinite permeability Free magnetic poles magnetic charges are induced on the surface of shields by the magnetic fields acting on them This surface charge distribution acts as a field source in the system Rectangular numerical meshes are defined for the bounding faces of the shield in order to compute the surface charge distribution A shield is not characterized by magnetization vectors Probe A probe is primarily used to extract the value of an output data at a point in space The location of the pro
34. arrays probes and shields the definition of mechanical motions electrical circuits group and component level data output etc All of this is accomplished with the design manager The design manager consists of two areas A tool bar at the top for adding new components or to import external designs and the System structure list below that lists the system and its components Right clicking the mouse anywhere in this list displays a pop up menu for carrying out the actions of the design manager 4 The External field controls no 3 in Fig 3 1a for specifying the type of external fields that will be applied to a system during a simulation 5 The System display pane no 4 in Fig 3 1a where a three dimensional depiction of the design is drawn The pane is continuously updated as components are added to or removed from the design and as the design is modified in other ways The user can modify the displayed design directly with the mouse or interact with and display different views of the system as well as modify its properties A pop up menu for accomplishing many tasks is displayed by right clicking the mouse anywhere in the System display pane fl MagSimus Deluxe Version 3 0 SUPER USER WritingDots mus Fil dow External Field Controls I Use feld definitions Ed of ff
35. back recordings Manual Auto Auto Repeat In the Manual mode only the next frame of the recording is displayed whenever either the Forward play button or the Reverse play button is pressed In Auto mode the recordings are replayed to completion in the corresponding directions whenever the playback buttons are pressed In Auto Repeat mode the recording is played back repeatedly in the forward and reverse directions Simulation area A simulation is initiated and controlled in this area Run in background Checking this box will cause the simulation to run in the background Run Simulation Starts a simulation to compute the physical response of the system Pause Pauses an on going simulation recording playback or motion display Stop Stops an on going simulation recording playback or motion display Lower tool bar of main program window System display tool bar The lower tool bar of the main program window Fig 6 5 provides system display tools for interactively manipulating the design shown in the system display pane of the System View window This tool bar is described in detail in Chapter 7 Leos ce i Dnaispay New MT zie Fig 6 5 Lower tool bar of main program window consisting of system display tools 1 component ock unlock button 2 zoom full button 3 zoom box button 4 zoom last button 5 zoom out button 6 rotate button 7 perspective view button 8 undo button 9 redo button 10 show moti
36. box see Chapter 6 Specifving design components The field at the target element is found as the volume average of the contributions of the segments H Shy 16 where hj 1 V h is the volume averaged field of the k th segment of the j th source element V is volume and h is the contribution of a source segment The field generated by the current flowing through the source segment Fig 5 4b is given by the Boit Savart law Cheng 1989 IA Ax i D 17 474A IR where is the length vector of the source segment in the direction of the current A and A are respectively the cross sectional areas of the source component and its segment respectively in a plane normal to the current direction R is the radius vector from the center of the segment to the field point and r R R is the unit vector in the direction of R The subdivision into segments for an array component is carried out for an imaginary limiting rectangular box bounding the array It can easily be proven that the field acting on an element or single array cell due to its own current is equal to 0 The self current field averaged over an entire array component is also 0 However individual cells of the array will experience non zero fields due to the current flowing in the other cells of the array a b Fig 5 4 Field due to current in element a Subdivision of elements into segments b Geometry of segment used in calculating field at p
37. box is described under the section Rotating components below 7 Perspective view Pressing this button displays a dialog for specifying the manner of rendering the perspective views of components of the design 8 Undo Pressing this button reverses the last change to the geometry of the design due to direct user mouse action on the system display pane or changes made with the dialog that is launched by pressing the Rotate button It also reverses the actions of the Redo button The maximum of number of undo actions that can be carried out for the design is specified in the box Maximum depth of system undos of the General tabs of System Specifications dialog box for a description of this dialog box refer to the topic Specifying the properties of the system object in Chapter 8 9 Redo Pressing this button re instates the last change that was reversed by pressing the Undo button 10 Show motion Pressing this button causes defined motions in the system to be played out in the system display pane Pressing this button while a motion is being displayed terminates the display and returns the design back to its initial state The design geometry is also returned back to its initial state after the motion has been displayed 11 View This is a drop down list of different projection views front back left right top bottom of the design The design is re drawn to reflect the selection made from this list 12 On display This is a d
38. by the user by direct mouse actions in the system display pane The open lock image shown here is displayed when compo nents are unlocked The image changes to that of a closed lock when components are locked 2 Zoom full Pressing this button displays the system so that it fills up the extent of system display pane 3 Zoom box Pressing this button initiates zooming action to display a specified rectangular region of the system display pane as follows Click and hold down the left mouse button over one corner of the intended zoom region Without releasing the mouse button drag the mouse to the intended corner opposite the first and release the mouse button A rubber band rectangle of the zoom is swept out while dragging the mouse and this region is displayed to fill up the extents of the system display pane 4 Zoom Last Pressing this button displays in turn views of the design at prior used extents of the system display pane This sequence of views continues indefinitely in wrap around order The maximum number of views that can be recalled is specified in the box Max stored system views ofthe General tabs of System Specifications dialog see Chapter 6 Specifying design components 5 Zoom out Pressing this button progressively expands the scale of the system display pane making the displayed design appear smaller 6 Rotate Pressing this button displays a dialog for rotating compo nents of the displayed design This dialog
39. can be defined to act on the system by pressing the Edit button Each field leg can be of variety of types Single Loop Rotation or Pulse and the external field is said to be of a corresponding mode when acting on a design A Single field is one of fixed magnitude and direction that is applied to the design A Loop is a closed field excursion applied to the design in a fixed direction of space A Rotation field is one whose direction and magnitude can change A Pulse is a field of limited duration that is switched between two field amplitudes along a fixed direction The dialogs for specifying fields are discussed later on in this chapter Use field definitions Checking this box indicates that an applied field sequence that is defined by clicking the Edit button are to be used in simulations Checking or un checking this box enables or disables the Edit button Edit Pressing this button displays a dialog boxfor defining external field legs and parametric simulation variables for a description of this dialog box see the section External fields and simulation specifications below Field Mode The external field mode is displayed here Scale Displays and specifies the scale of the field display pane This scale is the length of the half width or half height of the field display pane both of which are equal Magnitude Displays and specifies the magnitude of the active field Changes in the applied field due to a change in the magnitu
40. computer operating system Note Magsimus currently queues simulations for background execution in the order they are submitted Under this scheme only one background job runs at a time Monitoring background jobs Magsimus provides a means for monitoring the progress of background jobs The Background job monitor shown in Fig 6 11 is used for this purpose This window is displayed by selecting the main program Special gt Background job monitor menu The window consists of three framed parts that contain information about the currently running job the queued pending jobs and the recently completed jobs Read only boxes provide information about PIDs submitted time etc for the jobs making a selection in the queued or recently completed job lists displays information for the selection The Delete job buttons are used to delete jobs in the job areas Magsimus regularly saves the current states of running background jobs to their source files at the end of a pre determined number of equilibrium solution states This pre determined number is 1 by default The final state of a simulation that terminates normally is also saved to file by Magsimus The frame Job control actions provides the means for controling certain aspects of a running background job after its Apply button is pressed Send terminate signal Checking this box instructs Magsimus to terminate the job after it has written its next equilibrium solution state Equ
41. current profile editor is redrawn with the appropriate dialogs to allow editing for the profile type selected The profile editor for a pulse train is shown in Fig 8 19 Electrical current waveform specification l Type Pulse train Leg fi of 1 Signal pattern Max current level mA Min current level mA No rise time steps Delete Na fall time steps Clone No pulse duration steps Clear All No Quasi Static sample points Preview ET owne A e TT OK Cancel Help Fig 8 19 Dialog box for specifying current profiles I Type This is a drop down list of current profile types Pulse Train Harmonics The selection from this list will be the operational profile type for the leg currently being edited I Leg This is a drop down list of the leg positions of the electrical current sequence Selecting an item in this list displays its definition in the profile editor area Add Pressing this button adds a new leg to the field sequence Delete Pressing this button deletes the currently selected leg The user is prompted to confirm the deletion Clone Pressing this button identically replicates the selected leg and appends the new entry to the I Leg list Clear all Pressing this button removes all current profile leg defini tions The user is prompted to confirm the deletion Preview Pressing this button displays a window that shows a plot preview of the leg that is curre
42. data input specifications and generated output data will be independent of time During quasi static calculations applied fields are dependent on time while magnetization is time independent This approximates conditions in which the magnetization changes in the material occur at a much faster rate than the changes in magnetic field In this case input specifications and generated out puts are dependent on time however the transient solution states are indepen dent of time Magnetization and field are both time dependent in dynamic simulations The non equilibrium magnetization states are also time dependent in dynamic calculations All input specifications and outputs are time depen dent in this case The magnetization of an element or the cell of an array is modeled by the Landau lifschitz and Landau Lifshitz Gilbert equations Dif ferent forms of these equations are used for the different calculation methods Refer to Chapter 5 for a description of these equations Iteration Control area Use default method Use user defined method options These choices allow the user to specify whether dynamic calculations are to be car ried out according to the default program solution technique or in consider ation of certain user imposed constraints Remarks Internally dynamic calculations are carried out by means of a self correcting and variable step size differential equation integrator The default method uses any number of generally vary
43. definition substitute if a user defined definition cannot be found Fig 8 5 A patterned array on display showing an electrical source connected to the component through contact tabs in the u input and v output axes The output contact consists of 2 panels The current density vector distribution in the array is also shown About displaying component specification dialog boxes The properties of the design components elements arrays probes shields and field arrays making up a group are entered in their respective specification dialog boxes These dialog boxes are displayed using one of the following methods 1 To initiate the addition of a component by pressing the its icon in the action tool bar of the design manager see the topic Integrated Design Manager in Chapter 7 2 Double clicking the mouse on the component s icon on the System structure list This action loads the dialog box of the component for editing 3 Right clicking the mouse on the components icon if editing or anywhere else if adding a new component within the System structure box and selecting Edit or Add component from the displayed floating menu where component stands for Single component Array Magnetic shield or Probe 4 Double clicking the component in the System display pane Element and Array Specification dialog boxes These dialog boxes are used to specify the geometric magnetic and electrical properties of elements and arrays
44. description of the Materials Library dialog box Magnet Type Selects the magnet type of each cell of the array An icon corresponding to the selected magnet type is displayed to the right The magnet types are Normal magnet Ferromagnet with a magnetization of constant magnitude that is free to rotate in three dimensions Pseudo Soft magnet Ferromagnet with a variable magnetization magnitude that is free to rotate in three dimensions Permanent magnet Ferromagnet with a magnetization of constant magnitude and orientation in space Non magnet Non magnetic element Magnetization area Magnetization magnitude Specifies the magnetization of the array For a soft magnet array this is the saturation magnetization of an array cell Vector distribution coordinates This does not apply to an ele ment Specifies the angular coordinates Azimuthal Polar and the angu lar deviations Deviation of the initial orientations of the magnetization vectors of the array cells in the local coordinate system of the array uvw Temperature coeff Specifies the the temperature coefficient of the shape anisotropy of the component see the topic Thermal modeling of anisotropy in Chapter 5 Seed The random number seed for generating the orientation of magnetiza tion vectors Note For an element this area is called Vector orientation and only the angular coordinates Azimuthal and Polar characterize the direction of the single magnet
45. field and T is temperature Different temperature coefficients can be specified separately for different magnetic anisotropy terms defined for an object An un related random perturbation solver procedure for testing the stability of converged states offers a natural thermal vibration effect for the model It should be noted that the magnetization magnitude of an individual single domain cell is preserved in this model the cell s switching field magnitude however decreases with increasing temperature making its magnetization more susceptible to reversal Stochastic Thermal Model The stochastic thermal model follows the treatment described in detail elsewhere Tsiantos et al 2002 Each computational cell is subjected to an additional effective temperature dependent fluctuation field of fixed magnitude that varies randomly in direction from cell to cell This randomness is uncorrelated in space and time and thus produces a white noise effect The model in its original form applies exclusively to dynamic calculations however a formal extension of it to quasi static calculations is provided by Magsimus Deluxe The thermal fluctuation field magnitude is given for dynamic calcula tions by TM 2akpT h 36 AtyMV and for quasi static calculations by kpT B Hy Op fae 37 where Q is the damping constant of the LLG equation 3 is the Boltzman s constant T is temperature Af is a characteristic thermal settling ti
46. iliis 111 Environment Settings dialog box lliee eres 112 Tip of the day window liiis hh 121 Recording playback Carousel isllieeeeee es 122 Batch Job Manager sslssseeeeeeee VENEA EAS 124 Background joba erc oculi em ce mr dae eee dee eed das 126 Monitoring background jobs 0 0 cee 126 Chapter 7 Magsimus Reference System views 129 INMHOGUCHON 3 4245 cade dene pest Red deen ae adn Hd ake T ded ad ee RER Rid A aren 129 System view window Overview 0 00 cee eee 130 Integrated Design Manager 0000s 131 Action tool bar uus spei owed aa oe RE eae eae a bee d 133 System structure box 2 eee hn 134 Design Manager popup menuS 2 0000 c eee eee eee eee 134 External Field Controls 0 00 c eee eae 136 System display pane 0 0 0 eee 138 Mouse actions at the System display pane 200000e seers 139 System display pane action menus 00 00 eee 141 Lower tool bar of main program window System display tool bar 146 Rotating Components 0 000 hh 149 External field and simulation specifications 0000 eee eee eee 150 External field type inputs 2 2 153 Report WindOWS 0 2 4 2 ni Reel bbe ha E a TR rp PRAE 158 Manually moving group and components precisely 000 eee eee eae 160 Chapter 8 Magsimus Reference Component specifications 161
47. in the carousel that is from top to bottom or randomly The play back can be paused or stopped by pressing the Pause or Stop buttons in the simulation controls of the System view window The recorded simula tions in files are played back in their normal forward direction when the files are loaded The carousel playback is paused if a file that does not contain recorded simulation is loaded In this case the carousel playback is continued by pressing a Pause button 5 Skip backwards Pressing this button during carousel playback skips to the previous file in the playback sequence 6 Add item Pressing this button adds a new design file to the carousel Multiple items can be selected at once in the displayed Windows file open dialog box 7 Delete item Pressing this button deletes the selected design file of the carousel 8 Options Pressing this button displays a dialog for controlling the recording playback process 9 Help 10 List of design files contained in the carousel Double clicking an item on this list displays a message box with its full path name Other controls Repeat all Checking this box causes the playback of the carousel to repeat itself indefinitely Randomize playback sequence Checking this box causes the carousel to play back files in a random sequence Batch Job Manager The Batch Job Manager is used to specify and run a sequence of simula tions You typically complete the designs separately Y
48. in Oe Oersteds Magnetization expressed in kA m is numeri cally equal to magnetization expressed in emu cc To convert a field expressed in Oe to kA m divide by 4x The user may specify the default units for all newly created designs under the Units tab of the Environment settings dialog box see the topic Environment settings dialog box in Chapter 6 Group Specification dialog box The geometric magnetic and electrical properties of a group are specified by using the Group specification dialog box Figs 8 2a b 8 3 and 8 4 This box is displayed by one of the following actions 1 To initiate the addition of a group by pressing the Group icon in the action tool bar of the design manager see the topic Integrated Design Manager in Chapter 7 2 Double clicking the mouse on the group s icon on the System structure list This action loads the dialog box of the group for editing 3 Right clicking the mouse on the group s icon if editing the group or anywhere if adding a new group within the System structure box and selecting Edit or Add Group from the displayed floating menu 4 Double clicking the group in the System display pane Related input fields are organized as tabbed dialogs in the Group Specifi cation dialog box The tab dialogs with the exception of the motion and data output tab are discussed in this section The motion tab is discussed later on in this chapter under the topic Specifying motion while the data output
49. it by dragging the mouse to the new location The element can be stretched that is made bigger or smaller in size by clicking and holding down the left mouse button at any of its handles and dragging it All types of components with the exception of probes can be stretched this way A probe cannot be stretched Try out a few of these actions on the displayed elements to see their effects nii ele ile Fig 3 8 Main program system display tool bar 1 component lock unlock button 2 zoom full button 3 zoom box button 4 zoom last button 5 zoom out button 6 rotate button 7 perspective view button 8 undo button 9 redo button 10 show motion button 11 System view drop down list 12 On display drop down list The system display tool bar shown in Fig 3 1c and reproduced in Fig 3 8 can be used to further interact with the displayed design Pressing the Undo button reverses the last geometric change made to any of the elements The Redo button re instates the change Press the Undo button several times until the system is returned to its original geometry the Undo button becomes disabled when this happens Press the Lock Components button its icon changes from an open lock to a closed one in order to lock the displayed elements in place so that their geometry can no longer be interactively changed Pressing the Lock Components button again unlocks the component We will leave the Lock Components button in t
50. menu items applies the appropriate high pass filtering to the various x and Y data sets High pass filtering 1s obtained from the inverse transforma tion of Fourier data in which the spectral components lower in absolute values than a prescribed threshold value are suppressed The threshold spectral value is specified in the dialog box displayed by selecting the Spectral filter settings menu item see below Band pass X Band pass YorBand pass X Y Selecting any of these menu items applies the appropriate high pass filtering to the various x and Y data sets Band pass filtering is obtained from the inverse transforma tion of Fourier data in which the spectral components whose absolute values lie outside a range bounded by prescribed maximum and minimum threshold values are suppressed The threshold spectral values are specified in the dialog box displayed by selecting the Spectral filter settings menu item see below The Spectral data type menu item is active only if a X or Y Fourier spectrum plot type see above is selected It displays curves of the following sub menu items representing the characteristics of a Fourier transform Real part Imaginary part Amplitude and Phase Selecting the Spectral filter settings menu item displays the dialog box shown in Fig 8 13 In this dialog box the Filter type frame contains a variety of options for the filters Low pass High pass or Band pass that can be applied to data sets X Y or
51. method see for example Press 1986 is used to integrate the system of differential equations written for the components of the system Static Solver The magnetization of the system is independent of time for static calcula tions This is equivalent to treating the system as an infinitely damped system The implication of this assumption is revealed if we examine its impact on above dynamic equations Consider the LL equation the same argument goes for the LLG equation If the damping factor is infinitely large i e 4 oo the equation transforms to M x M x H 0 5 It is obvious that a magnetization vector that is parallel to the applied field will satisfy this equation For reasons of stability and to account for cooperative effects between the magnetization vectors the solver does not bring the magnetization vectors all at once to full alignment with applied fields but instead rotates them incrementally towards the fields The amount of rotation at each iteration is proportional to the magnitude of the vector triple product on the left hand side of eq 5 Pseudo soft magnet response The magnetization of a pseudo soft magnet is given by M u 1 H 6 where p is the relative permeability diagonal tensor of the material of the element and 1 is a unit matrix The magnitude of the magnetization vector is truncated at the saturation magnetization of the element Magnetic shield model Magnetic shields represent ideal
52. more complicated anisotropies for the array by combining several simple anisotropies Refer to Chapters 4 and 5 for more information on magnetic anisotropies Note The definition of anisotropy is irrelevant in the calculations of non magnetic and permanent magnetic arrays There is no limit to the number of anisotropies that may be defined Magnetic Anisotropy area Type Specifies the type of magnetic anisotropy currently being defined for the array Uniaxial or Pinning Field Specifies the anisotropy field for the anisotropy currently being defined for the array Orientation of easy axis within element Specifies the angu lar coordinates of orientation Azimuthal Polar and the angular devia tions among array cells Deviation of the easy axis directions of the anisotropy currently being defined in the coordinate frame of the array uvw Temperature coeff Specifies the temperature coefficient of the anisot ropy of the component see the topic Thermal modeling of anisotropy in Chapter 5 Seed The random number seed for generating the orientation of anisotropy vectors Note The angular deviation is not used in element specification dialogs No Drop down list of the ordinal positions of defined anisotropies of the array Selecting an item of the list fills all the input fields with data entered for the selected anisotropy definition Define New Pressing this button defines a new anisotropy Delete Pressing this button dele
53. o Nos id charges for all faces aces to turn o Magnetization emu cc 800 istas J 2ndUViface jv 1stU W face 2nd U W face Type TstV W face V 2 e Isotropic Relative permeability Value 2000 Positive infinite Interact with all system components Components 1 2 Er free pa Direction of current in component u Axis M Add Delete C OK Cancel Help Fig 8 9b Electromagnetic tab of Magnetic Shield specification dialog The electromagnetic properties of a shield component is defined here Fig 8 9b This dialog also allows the user to imbue a variety of additional properties to the shield component by being able to selec tively disable the sides of the shield as well as explicitly specify the components of the system the shield can interact with The mathematical model of the shield component is discussed in the section Magnetic shield model in Chapter 5 Conductivity Specifies the electrical conductivity of the shield Magnetization Specifies the saturation magnetization of the shield Relative permeability area Value Specifies the relative permeability of the shield to be used in calcula tions if the Normal option is selected Normal Selecting this option indicates that the relative permeability speci fied in the Value field is to be used in calculations Positive infinity Selecting this option indicates that the shield has a relative permeability of plus infinity the entry in
54. of a cell during calculations Model Specifies the dynamic equation type Landau Lifschitz or Landau Lif schitz Gilbert that is to be used to model the cell response during calculations Field vector conditionings area The selections Ignore u component of field Ignore v com ponent of fieldand Ignore w component of field specify which of the local components of the total field acting on the array are to be excluded in calculations Use volume average magnetostatic fields If this box is checked then the effective field acting on an array cell is the field averaged over its volume otherwise the field value at the center point of the cell is used in calculations Ignore self demagnetizing fields of array cells Checking this box turns off the inclusion of the self demagnetizing field term in the total magnetic field acting on the cells of the array during calculations Note The self demagnetizing field of a cell depends on its shape This captures the shape anisotropy behavior of the average real grain that is represented by the cell By turning of the self demagnetizing fields one effectively uses the array lattice choice simply as a means to specify field points the centers of the cells within the array Ignore intra array magnetostatic interactions Checking this box turns off the inclusion in calculations of the field term representing the magnetostatic interactions between the cells of the array Magnetostatic truncati
55. of minus infinity Anisotropic Selecting this option indicates that the relative permeability is anisotropic and is characterized by the diagonal tensor values T uu T vv and T ww Direction of current in component Specifies the direction of electrical current flow through the component Magnetic Anisotropy tab FA il Array Specification 1 1 Array of 4 magnetic cells Lines and Colors Calculation Control User defined Params Data Output Stimuli sources Electromagnetic r rop Exchange Coupling Magnetoresistance Magnetic Anisotropy Type Uniaxial C Pinning No 2 of 2 Field Oe 20 Define New Orientations of easy axes in array Deg Azimuthal 20 Deviation 0 Delete Polar 45 Deviation 10 Seed 1234 Temperature coeff De K 0 OK Cancel Help Fig 8 6c Magnetic Anisotropy tab of Array specification dialog box Magnetocrystalline magnetic anisotropies of the array is defined here Fig 8 6c These anisotropies promote a preferred orientation of the magnetization vector at each array cell The simplest magnetic anisotropy defined for each cell is either a uniaxial or pinning anisotropy which are both characterized by an anisotropy field and easy axis An anisotropy variation can arise in the array owing to differences in the orientations of the anisotropies of its cells Uniaxial anisotropy is bi directional while pinning anisotropy is unidirectional This window allows the definition of
56. on its electrical conductivity Thus in circuit calculations a patterned array is treated just as an un patterned one Giant magnetoresistance GMR The formulation for GMR in the software is a generalization of a previous phenomenological GMR theory Oti 1997 that is applicable to magnetic components that form parts of general electrical networks Phenomenological models are derived from bulk observations This distinguishes them from first principle models that are based on electron transport theory Excellent reviews of the phenomenon of GMR exist in the literature see for example White 1992 The phenomenological model employed by Magsimus Deluxe combines the usual magnetization cosine dependence of resistance change with a dependence on current distribution in the magnetic components These effects are accounted for in calculating the changes in the local conductivities due to GMR of the individual computational cells making up the magnetic components The calculation of GMR can be carried out for a design group of compo nents or for element and array components individually We say that a component is GMR coupled to any of its neighbors if its GMR behavior is affected by the magnetization of the neighbor The effect of GMR on the conductivity o of a design component the target is given by o Cr Ag 24 where o is the intrinsic conductivity of the component and Ao is the change in conductivity due to GMR given by
57. option in Calculation tab dialog of System specification dialog 165 Calculation control System display pane action menu 146 Calculation control dialog box 77 146 Calculation control tab 78 Calculation Method area in Calculation tab dialog of System specification dialog 163 Calculation method frame in Calculation control tab dialog of Environment Settings dialog 119 Calculation methods 19 Calculation steps 66 Cancel button in Importing components window 226 Cancel simulation button in parametric output window 215 Carousel 107 230 Cellider array patterning utility 12 13 Cells array outline type 142 Centimeter cm 116 CGS 116 CGS units 20 check pointing 52 114 Check pointing a simulation 166 Check pointing area in Calculation tab dialog of System specification dialog 166 Cheng D K 78 96 Classic Thermal Model 93 Clear All button in dialog for specifying output data for a group 207 Clear all button in Motion tab of the Group specification dialog 175 in system external field specification dialog 151 Clone button in system external field specification dialog 151 Clone Leg button in Motion tab of the Group specification dialog 175 Clone menu in integrated Design Manager 135 Color button in Plot settings dialog box 213 in Color attributes tab dialog of Environment Settings dialog 119 in General tab dialog of System specification dialog 163 Color attributes for new designs area in Color attributes tab di
58. required simulation output definitions Organize the components into groups and specify group outputs as needed It helps to plan ahead before actually beginning the design process You can add as many components of different types and properties as you please your only constraints are your imagination and the capabilities of your computer Consequently you can simulate those designs you are already familiar with as well as explore new uncharted territory Step 2 Add design attributes such as motion and electrical circuit param eters to your design as required Step 3 Specify any needed external fields to be applied to the design Step 4 Run a simulation computation on your design to generate specified outputs Recording your simulation provides you with added flexibility in analysing your design further We highly recommend a bottoms up approach in creating all designs from the simplest designs to the more complex Always strive to fully characterize individual sub systems of the design before including them into your final design Magsimus design importation capability can greatly facilitate this approach Tutorial 2 Parametric simulation example We conclude with a tutorial of a simple design example that illustrates the parametric simulation capabilities of Magsimus A parametric simulation is one that is repeated several times using different values of one or more design properties parameters which are varie
59. s magnetic properties such as magneti zation anisotropy pinning fields and electrical conductivity can also be selected from a convenient materials library Furthermore the user may define auxilliary non material field array or probe components These permit the sensing and visualization of electromagnetic vector fields and various output quantities at different regions of the design Electrical circuits can be specified and currents applied The elements interact through magnetostatic interactions and user specified exchange interac tions Components are organized into groups to allow different structures to be built up and manipulated independently Relative translation and rotary motion between the groups can be specified For example one can design a group that describes an advanced recording head and a group describing the magnetic structure of media These two groups can then be moved relative to each other in a way to simulate the recording process The magnetic behavior of a system can be calculated under static quasi static and dynamic conditions Magsimus offers a rich repertoire of possible outputs that includes the magnetization and magnetoresistance of groups and components of the system The user can generate output in the form of a movie of the evolution of the magnetization of the design The system configuration and output data can be conveniently saved to disk files for further analysis The chapters of this manual
60. selections from the displayed popup menu The popup menu also allows the editing insertion deletion and cloning of components the discretization of elements and the patterning of arrays Cloning produces an exact copy of the selected component and appends it to the system The discretization of an element converts it into an array Patterning of an array is the selective eliding of its cells to create more complicated geometric struc tures Populating the first group Let us now proceed by creating the components for our initial currently empty group We first replace the default names of the system and group in the System Manager with more meaningful ones To change the system name first highlight its entry in the System structure list by clicking on it once Then click on it a second time to start editing its text Change the text to Test design Carry out the same steps for the group entry and change its name to Group of electrically energized nonmagnets This group will contain two nonmagnetic elements that will be connected electrically to each other and fed by an electrical current source We now add these elements To add a new element click on the element button of the Design Manager this is the second button from the left in the action tool bar The Element Specification window shown in Fig 3 4 is displayed It is here that among others the geometric and electromagnetic properties of an element are specified Related
61. sequentially in the order they appear in the motion definition In the dialog box of Fig 8 3 linear and angular velocities are expressed in nm step and Deg step for static calculations and in nm s and Deg s for dynamic and quasi static calculations Motion Leg No Selects a motion leg to edit The attributes of the currently selected leg are displayed in various input fields in this dialog tab Return group to this leg s initial position after it terminates Checking this box will cause the group to be returned to its starting coordinate position at the onset of the motion leg after the leg ends Add Leg Adds a new motion leg for the group Delete Leg Deletes the currently selected motion leg of the group The user is prompted to confirm the deletion before it takes place Clone Leg Clones identically replicate the currently selected motion leg of the group Clear all Deletes all defined motion legs of the group The user is prompted to confirm the deletion before it takes place Translation velocity Defines the direction Azimuthal Polar and magnitude Magnitude of translation velocity of the group being edited in the currently selected motion leg The angular coordinates are specified relative to the system coordinate frame Number of Motion Steps Specifies the number of steps to be taken in the currently selected motion leg Duration of motion Applies only to dynamic simulations The physical time length of
62. simulation runs for all newly created designs to occur by default in the background Automatically scale new output curves Checking this box causes the axes scales of curve plot windows to be automatically adjusted to accommodate newer points that fall outside the plot window Plot data markers for new output curve plots Checking this box causes new curves traced out in the plot window to include data point markers Design projection attributes frame The inputs here defines the default perspective projection properties of a design in the System display pane This gives the user additional flexi bility in enhancing the manner of displaying a design to suit his her preferences Projection method This is a drop down list from which the projection type Cabinet Cavalier or Planar can be selected Projection angle Specifies the projection angle to be used for the cho sen projection method Always express exchange using frame The selection within this frame Field or Exchange parameter A causes all relevant input boxes in the software to accept exchange coupling strength inputs expressed as a field or as a related exchange A parameter Default input types for geometric origins frame The inputs here define the default meanings of the geometric origins of new design groups and components when their properties specification dialogs are displayed Group This is a drop down list from which group options Relative to the previ
63. soft magnets A recent paper Oti 2001 describes in detail the magnetic shield model that is implemented in Magsimus This is a novel technique that enables the modeling of linear saturable finite sized three dimensional shields Fig 5 3 Illustration of meshing of the faces of a magnetic shield component When shields are subjected to magnetic fields free magnetic poles are induced on their surfaces The induced poles act as field sources in the system Rectangular meshes are defined on the bounding faces of the shields Fig 5 3 to obtain the surface pole distributions Each individual cell of a mesh is referred to as a panel The pole at a surface point is obtained by invoking image boundary conditions that must be satisfied at a shield surface point The surface pole density is assumed to be constant within each panel of the surface meshes The center of a panel is used as the reference point for calculating the pole density The induced pole density at a surface point is given by 9s u 1 r Hy n 7 where H is the total field from all sources acting at the surface point p is the relative permeability of the shield and n is the external normal to the shield surface For an ideal shield p the induced pole density is o H n The saturation of the shield imposes physical limits on the magnitude of the induced pole density This is expressed by the saturation condition 5 lt M 8 where M is
64. system in order to achieve self consistent solutions Calculation Method area Static Selecting this option indicates that static simulations will be carried out f System specifications x General Calculation control Electrical Circuit Units Calculation Method Iteration Control C Static There model Use Default method Use user defined method Quasi static Classic Time step per iteration ns 0 1 i IV Apply this total time bound ns 20 Calculate to full relaxation Maximum number of iterations no C Convergence Tolerance Deg o M solution precision lt 1 0 000001 J Show equilibrium magnetic states Show transient magnetic states States sequence display pitch 4 Graphs re plot pitch 1 J Track M rotation angle Max M rotation angle Deg 5 v D Background mode equilbrium file save threshold 100 Check pt iteration threshold fio 0 w Restore initial system geometry at end of simulation Write simulation recording data to external file Fig 8 1b Calculation tab of System specification dialog Quasi static Selecting this option indicates that quasi static simulations will be carried out Dynamic Selecting this option indicates that dynamic simulations will be carried out Remarks For a static calculation both the magnetization and magnetic field components are independent of time Consequently with this method both
65. system of design components Component origin in group coordinate frame Specifies the location of the origin U V W of the component in its group The selection in the Input type box Relative to previous component Relative to the group origin determines how the origin input is to be interpreted The default input type can be specified in the in environment dialog box reached by selecting the main program menu item Special gt Environment settings Angular orientation coordinates within group Specifies the angular orientation coordinates Azimuthal Polar of the array measured relative to the coordinate frame of the parent group of the array Size of array cell Specifies the linear dimensions Length Lu Width Lv Thickness Lw of each array cell along the local coordinate axes Note For an element these dimensions give the linear dimensions of the element Spacing between cells This does not apply to an element Specifies the spacing between array cells Along u Along v Along w Array matrix dimensions This does not apply to an element Specifies the dimensions of the three dimensional cell matrix of the array Along u Along v Along w Each dimension gives the number of cells along the corresponding coordinate axis Electromagnetic tab Array Specification 3 1 Array of 4 magnetic cells Lines and Colors Calculation Control User defined Params Data Output Ji Stimuli sources
66. system to be restored at the end of a simulation Write simulation recording data to external file Checking this box will cause recorded data to be written to an external file The record file is located in the same folder as the design file and its name is derived from the design file using the convention designfile erf mdb for example the record file for a design file name MySensor mus will be named MySensor_erf mdb Remarks By default recorded simulation data is held in main memory This could take up too much memory if the size of the design is large and many design states are recorded This problem can be alleviated by recording to file Whenever a loaded design in Magsimus that has a record file associated with it is saved to a different folder the record file is moved to the new folder Check pointing area Magsimus provides the powerful check pointing feature that allows partial recovery from prematurely terminated simulations The simulations may end abnormally due to a variety of reasons such as a sudden system crash or the premature expiration of a license in the middle of a simulation During check pointing Magsimus creates periodic backups of an on going simulation that contain all needed information for potentially re starting it When Magsimus is re started following a crash it searches the application directory for a check pointed file If it finds one it restores the design and prompts the user with the option of cont
67. the damping term because it simulates energy loss damping mechanisms in real materials that cause the magnetization vector to tend to line up with an applied field The LLG equation is variously expressed in two forms dM e 2l _ au MEAS ygM x H M x7 3 and a M ty M x H G jM x M x H 4 where yg is the Gilbert precession factor and og is the Gilbert damping factor The latter form of the LLG equation is called the Landau Lifschitz form because of its resemblance to eq 2 The precession factors in 2 and 3 are equal y yg 1 105 x 10 m A s where g is the gyromagnetic ratio However note by comparing 2 and 3 that the effective precession factors for both equations are different Although the gyromagnetic ratio is customarily believed to assume the values 1 and 2 in nature Magsimus allows the user to specify other values for it In the LLG equation the precession and damping are coupled to each other through the damping factor g These terms are not coupled to each other in the LL equation The predicted angular velocity of precession when using the LLG equation decreases with increasing damping for the LL equation the predicted angular velocity is independent of damping Both equations can be mixed during a dynamic simulation The choice of equation for a magnetic element can be made from the dialog box used to specify its properties A variable step size error correcting Runge Kutta
68. the motion Angular velocities of rotation Defines the angular veloc ities of the azimuthal and polar angular coordinate of the group Azimuthal Polar These angles are measured relative to the system coordinate frame Specifying electrical contacts for arrays The design components that are connected into a group s electrical circuit are characterized by their electrical contacts Note The contacts do not add additional resistance to the circuits They merely mark where current enters and leaves the component For single components that are connectable in a circuit elements and shields the contact area of the leads spans the entire surface of the input output ends of the component Additionally for arrays the electrical contacts can be defined to span only a subset of contiguous cells on the input output sides of the array Each contact need not be one continuous whole but may consist of several smaller panels The dialog box for accomplishing this is shown in Fig 8 4 This dialog box is displayed in several ways 1 Right clicking the mouse on the component in the System display pane and selecting from the displayed floating menu the item Edit electrical contacts 2 Pressing the Edit elect contacts button under the Electrical Circuit tab of the Group specification dialog box see Fig 8 2 above 3 Pressing the Edit electrical contacts button under the Electromagnetic tab of a component s specification dialog box
69. will be brought to move during a simulation We have not defined this motion yet Motions will be defined in the next section The magnetization vector of the permanent magnet will be tilted in its local coordinate frame according to the specified vector orientation The design and all its components at this stage are displayed in Fig 3 9 You may need to use the zoom out and zoom box buttons in the main program tool bar to obtain the view in this figure tgp ere Lil Fig 3 9 System view window displaying all groups of the design Displaying individual design components Use the On Display drop down list of the main program tool bar to display the whole system a group or a group s individual component In the figure the entry Test design is currently selected thus the whole system is displayed on the system display pane Selecting a group or component from this list results in only that group or component being shown in the system display pane This feature allows the user to interact with individual groups or components separately from the rest of the system Specifying electrical circuit for first group We now add the remaining design attributes for our system beginning with the specification of a group electrical circuit connecting the elements of the first group The elements w
70. window Recording playback Carousel The recording playback Carousel feature Fig 6 9 is used to collate and play back existing recorded simulations The Carousel is displayed by selecting the menu Special gt Recording Play back Carousel in the main program window It may be used to great effect to illustrate a sequence of related simulations For example in magnetic recording simulations the first file of the carousel might be one illustrating the write process while a second file may illustrate the read process Carousel definitions are saved in carousel files with extensions crsl The collated recordings are played back sequentially according to a prescribed ordering 1 Open new Carousel Pressing this button loads in a new Carousel file 2 Save Carousel Pressing this button saves the current carousel to file You assign a name to a new carousel as you save it 3 Skip forward Pressing this button skips to the next file in the play back sequence during playback of the carousel ET Logol mus 10 AnistropyTie mus mr read head conceptmus Head over Longitudinal media 1 mus WrritingDots mus ReadingDots mus IV Repeat all Randomize playback sequence Fig 6 9 Recording playback Carousel window 4 Play Pressing the button initiates the play back of the carousel Remarks During playback the contents files of the carousel are re played one after another either in the natural sequence they are listed
71. with an array component Checking this box causes coupling to occur between the closest layers of the target and source components The Cou pling plane box is used to specify the orientation of the coupling layers These layers are either the first or last for a particular layer orientation depend ing on the relative locations of the source and target in the system hierarchy If the target is located earlier in this hierarchy because it belongs to an earlier group of the system or because it is an earlier component within the same group then the coupling layer is the last layer otherwise it is the first layer In interface coupling the first layer of the source layer is coupled with the last layer of the target or the last source layer is coupled with the first target layer Note When interface coupling is used in conjunction with the Apply cell to cell coordi nation in calculation option the coupling between layers occurs through corresponding cell to cell couplings Group Displays the description of the parent group of the component cur rently displayed in the Components list Components Drop down list of components that are currently coupled to Each component description is preceded by the notation n m where n is the parent group number of the element and m is the position of the component in the group The entries Field and Group change to reflect the definitions for the currently selected component Define New Pressi
72. 156 Run button in Batch Job Manager 125 Run button Simulation 42 43 Run in background box in Simulation area of main program s upper toolbar 110 Run jobs in background check box in Batch Job Manager 126 Run Simulation button 44 in Simulation area of main program s upper toolbar 110 S Sakakima H 96 saturation condition 74 Saturation magnetization 200 saturation magnetization 60 73 80 Save Main program menu item 106 Save As Floating menu in parametric output window 214 Save as Main program menu item 106 Save batch job button in Batch Job Manager 124 Save Carousel button in Recording playback Carousel 122 Scale box in External Field Controls 138 Second s 117 Seed in Electromagnetic tab of Array specification dialog 183 in Magnetic Anisotropy tab of Array specification dialog 185 Select button in Material library dialog 220 Select contact area in Electrical contact properties dialog box 177 Select field scope 41 Select field scope frame in system external field specification dialog 150 Select group list in system external field specification dialog 151 self demagnetization 75 self demagnetizing tensor 76 Self GMR response 87 Send terminate signal check box job control action in Background job monitor 127 Seshu S 65 96 session counts 13 Set 199 Set auto mesh button in Geometric tab of Magnetic Shield specification dialog 199 Set M color wheel scaling System display pane action menu 144 Se
73. 181 input type option in Geometric tab of Probe specification dialog 196 Relative to the system origin input type option in Geometry tab of Group specification dialog 171 Remote Licensing System 14 Removable media installation 12 Repeat all check box in Recording playback Carousel 124 Replay available recordings upon design load option in General Option tab dialog of Environmental Settings dialog 114 Replay Go to in main program upper toolbar 110 Replay Mode list in main program upper toolbar 110 Reports 158 System display pane action menu 145 Reset surface charges at start of calculations check box in Calculation Controls tab of Magnetic Shield specification dialog box 201 Reset swatch button in Electrical contact properties dialog box 178 Restore initial system geometry at end of simulation check box in Calculation tab dialog of System specification dialog 166 Return group to this leg s initial position after it terminates box in Motion tab of the Group specification dialog 175 Reverse play button 44 Reverse play button in main program upper toolbar 109 right view of design 148 Rise steps box in Pulse external field definition dialog box 157 rise time 67 Rise time box in Pulse external field definition dialog box 157 root node 161 rotary fields 230 rotary motion 8 Rotate button in main program lower toolbar 147 Rotating component dialog box 149 160 Rotating Components 149 Rotation external field
74. 96 that SMT can be effectively modeled by introducing an additional damping term in the LL equations 3 and 4 or equivalently by introducing a new spin momentum transfer effective field term H Magsimus defines this effective field to be compartible to its generalized GMR model N gmr o Ml elV pog l where A is damping factor m is the Bohr magneton e is electronic charge V is the volume of the target component M is its magnetization and is the magnitude of the electrical current flowing through it The summation in 29 is over the components that are GMR coupled to the target The selected neighbors are those for which traceable positive current paths exist between them and the target Momentum transfer is brought about by polarized incoming electronic flux from the neighbors flowing in opposition to the current m is the unit magnetization vector of each coupled component expressed in the frame of reference of the target component for which H is being computed for an array this is the volume average magnetization of the unit magnetization vectors of the array cells whose magnitude will not necessarily be 1 P sin 2 where 6 is the angle between the local magnetization and its neighbor is a measure of the relative polarization between the magnetization This formulation of the model applies equally well to two thin film systems of much recent interest single layer and multilayer sandwich structures SMT i
75. ASIS SHALL NOT BE LIABLE TO LICENSEE FOR MORE THAN THE AMOUNT PAID BY LICENSEE TO MAGOASIS FOR THIS SOFWARE COMPONENT WITH RESPECT TO WHICH THE LIABILITY IN QUESTION ARISES AS INSTALLED ON THE DESIGNATED COMPUTER FOR WHICH USE OF THE SOFWARE IS LICENSED HEREUNDER General Provisions Licensee may not assign this license except to a subsidiary or parent company of the Licensee Should any act of the Licensee purport to create a claim lien or encumbrance on any SOFWARE such claim lien or encumbrance shall be void All provi sions regarding warranty liability and limits thereon and protection of proprietary rights shall survive termination of this agreement as shall all provisions regarding payments of amounts due at the time of termi nation This agreement shall be governed by the internal laws of State of Texas USA Should Licensee install the SOFTWARE outside the United States Licensee shall comply fully with all applicable laws and regula tions relating to the export of technical data This Agreement is the entire agreement between MagOasis and you supersedes any other agreements or discussions oral or written and may not be changed except by written amendment signed by MagOasis This Agreement shall be governed by and construed in accordance with the laws of the state of Texas USA excluding its conflict of laws rules and the United Nations Convention on Contracts for the International Sale of Goods If any provision of this Ag
76. Base application subdirectory If this file is missing Magsimus creates one in its place whenever the user attempts to store information into the material library Graphical plot output files dat files These files contain the raw data of the graphical plots displayed in 2 D plot windows and in the surface cut trace and scan trace boxes of the parametric output window These files are generated by first right clicking the mouse in the respective plot boxes and then clicking the Save menu in the displayed floating menus The raw data information areas of these files are preceded by descriptive header information Headers separate individual scan outputs for parametric output data files Magsimus License Introduction MagOasis LLC software End User License Agreement provisions are of 3 types i Purchase License Agreement for Pay per use Licenses 11 Purchase License Agreement for Long Duration Licenses and iii Demonstration Evaluation license agreement Make sure you read the provisions that apply to you before using Magsimus Deluxe Magsimus Custom Applications Spin valve Bench etc or other MagOasis software Purchase license agreement for Pay per use licenses The following applies to you if you have purchased a copy of Magsimus Deluxe Magsimus Custom Application or other MagOasis software through our Pay per use Online Store This license agreement represents the entire agreement between you Licensee either an
77. Constant GH2 De 0 Ignore V component of field Gyromagnetic Ratio 2 Ignore W component of field Equation Landau Litschitz M IV Use volume average magnetostatic fields Ignore self demagnetizing fields of array cells Calculate array self field due to it s own current Ignore intra array magnetostatic interactions eM Magnetostatic truncation tolerance n 1 Cancel Help Fig 8 6g Calculation Control tab of Array specification dialog box Certain specifications that affect the manner in which the calculation of the magnetic field response of the array cells will proceed are entered here Fig 8 6g Dynamic equation properties area Note These entries apply only to dynamic calculations The response of each array to an applied magnetic field is modeled in calcula tions by either of two dynamic torque equations The Landau Lifschitz LL equation or the Landau Lifschitz Gilbert LLG equation Refer to Chapter 5 Mathematical Model for detailed information about the dynamic equations Damping constant Specifies the damping parameter that is to be used in the dynamic equation of a cell during calculations Note For the LL equation the damping constant is expressed in GHz Oe in the CGS system of units or in GHz kA m in the SI system of units The damping constant is dimensionless for the LLG equation Gyro magnetic ratio Specifies the Gyro magnetic ratio that is to be used in the dynamic equation
78. E does not materially operate as warranted Licensee s exclusive remedy and MagOasis sole liability under this warranty shall be 1 the correction or work around by MagOasis of major defects within a reasonable time of not more than 90 days from discovery or 2 should such correction or work around prove neither satisfactory or practical termination of license and a pro rated refund of the license fee paid to MagOasis for the SOFTWARE component FOR LICENSES OF DURATIONS OF 3 WEEKS 21 DAYS OR MORE PURCHASED IN SINGLE TRANSACTIONS PURCHASES OF 2 WEEKS 14 DAYS OR LESS ARE NOT ELIGIBLE FOR REFUNDS Important In order to process refunds customer must provide MagOasis with any requested license tracking files that may be generated from MagOasis software THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE MAGOASIS SHALL NOT BE LIABLE FOR ANY SPECIAL INCIDENTAL OR CONSE QUENTIAL DAMAGES INCLUDING WITHOUT LIMITATION LOST PROFITS Licensee accepts responsibility for its use of the SOFTWARE and the results obtained therefrom Limitation of Liability MAGOASIS SHALL NOT BE LIABLE TO LICENSEE FOR MORE THAN THE AMOUNT PAID BY LICENSEE TO MAGOASIS FOR THIS SOFTWARE COMPONENT WITH RESPECT TO WHICH THE LIABILITY IN QUESTION ARISES AS INSTALLED ON THE DESIGNATED COMPUTER FOR WHICH USE OF THE SOFTWARE IS LICENSED
79. Electrical contacts editor x Select contact Contact definition swatch press and drag left mouse button to specify tab area C Input Output Panel 3 of3 X1 Y1 X2 Y2 11 5 18 6 Delete Reset swatch Input current axis u Axis v Dutput current axis weis Y Contact display attributes Iv Show input contact tab Cancel Help V Show output contact tab Fig 8 4 Electrical contact properties dialog box The output electrical contact being edited consists of 3 panels represented by the 2 blue boxes and 1 green box in the contact definition swatch The green box represents the selected swatch in the Panel box Input current axis and Output current axis These are drop down lists for specifying the direction of current for the input and output contacts of the component one of the coordinate directions u axis v axis or w axis Select contact area The contact to edit input or output to edit in the contact definition swatch see below is selected here Electrical display attributes for component area The array contacts that are to appear when electrical circuits are displayed is specified here This is given by the state of the Show input contact tab and Show output contact tab check boxes Contact definition swatch The electrical contact areas panels and their location in the input or output ends of an array component is defined in the Conta
80. Electromagnetic Geometry Y Magnetic Anisotropy Exchange Coupling Magnetoresistance Material Magnet Type Aje Generic Pseudo soft magnet x IV Make this a tunnel junction Edit junction Conductivity MSm em 1 Magnetization Input current axis u Axi Magnitude emu cc 300 p u Axis Output current axis wais v Vector distribution coordinates Deg Edit electrical contacts T rere Relative permeability Azimuthal 0 Deviation 360 ba a Type Polar 0 Deviation 180 REI sotropic Seed 1234 pecan 100 Positive infinite T_vv 10 Negative infinite Temperature coeff emu ccK 0 T ww 100 Anisotropic Use initial demagnetized state in calculations OK Cancel Help Fig 8 6b Electromagnetic tab of Array specification dialog box The electromagnetic properties of the array being edited are defined here Fig 8 6b See Chapter 4 for more information on the electromagnetic properties of an array Material Holds a description of the material type of the array Pressing the button to the right displays a window for selecting a pre defined material type from a library of materials or adding the material definition of the current element to the materials library The material type for an element is defined by a magnetization value a conductivity value and defined magnetic anisotropies See the section Materials library later on in this chapter for a
81. HEREUNDER General Provisions Licensee may not assign this license except to a subsidiary or parent company of the Licensee Should any act of the Licensee purport to create a claim lien or encumbrance on any SOFTWARE such claim lien or encumbrance shall be void All provi sions regarding warranty liability and limits thereon and protection of proprietary rights shall survive termination of this agreement as shall all provisions regarding payments of amounts due at the time of termi nation This agreement shall be governed by the internal laws of State of Texas USA Should Licensee install the SOFTWARE outside the United States Licensee shall comply fully with all applicable laws and regula tions relating to the export of technical data This Agreement is the entire agreement between MagOasis and you supersedes any other agreements or discussions oral or written and may not be changed except by written amendment signed by MagOasis This Agreement shall be governed by and construed in accordance with the laws of the state of Texas USA excluding its conflict of laws rules and the United Nations Convention on Contracts for the International Sale of Goods If any provision of this Agreement is declared by a court of competent jurisdiction to be invalid illegal or unenforceable such provision shall be severed from this Agreement and the other provisions shall remain in full force and effect Should you have any questions concerni
82. Magnet types array magnetic properties 62 element magnetic properties 60 magnetic 228 Magnetic anisotropies array magnetic properties 62 Magnetic anisotropy anisotropy field strength 60 bi directional 60 easy axis 60 element magnetic properties 60 pinning 60 uniaxial 60 unidirectional 60 Magnetic Anisotropy area in Magnetic Anisotropy tab of Array specification dialog 185 magnetic anisotropy constant 80 magnetic anisotropy field 75 79 Magnetic Anisotropy tab 46 magnetic charges 63 Magnetic force output of 91 Magnetic list in Start up Units tab dialog of Environmental Settings dialog 116 Magnetic properties of array 62 of elements 59 63 Magnetic shield 63 Magnetic shield model 73 Magnetic Shield specification dialog box 197 Magnetic Shield specification dialogs Calculation Control tab 201 Electromagnetic tab 199 Geometry tab 198 Lines and Colors tab 202 Magnetic Shields 108 magnetic shields 55 228 magnetic torque 68 magnetic tunnel junctions 68 Magnetic Tunnel Junctions MTJ 90 Magnetization 230 in Electromagnetic tab of Magnetic Shield specification dialog 200 output of 82 Magnetization area in Electromagnetic tab of Array specification dialog 183 Magnetization magnitude box in Electromagnetic tab of Array specification dialog 183 Magnetocrystalline 69 Magnetocrystalline magnetic anisotropy 228 magneto motive force MMF sources 194 Magnetoresistance AMR 61 GMR 61 MR ratio
83. Magnetocrystalline anisotropy field 0 0 0 Exchange coupling field 0 0 0 Magnetostatic field excluding self demagnetization field 26 71494 38 31315 158 7307 zi Fig 7 17 The report window of an element Manually moving group and components precisely EI Moving component 1 Group C Component Horizontal nm 20 Vertical nm 40 Apply x NN p i iN Fig 7 18 Dialog box for moving design components There is often a need to manually move a group and or its components precisely in the system display pane This is accomplished by right clicking a group or component in the pane and selecting the action menu item Move group or component manually This action displays the Moving component dialog box shown in Fig 7 18 The displacements are expressed in the prevalent linear units of the system A component or group is moved by the specified amount after the Apply button is pressed Chapter 4 provides a description of coordinate systems of Magsimus Group and component options This selection indicates to which of the selected components in the System display pane the currently specified displacements will apply to When a component is selected in the System display pane its parent group is automatically selected as well Horizontal Specifies for the selected group or component the amount of horizontal left right displacement relative to the displayed system view Vertical Specifies the
84. Magsimus Deluxe General purpose micromagnetic design software Virtually Magnetic E Deri amp e J gx User Manual MagOsm MUSDV 600102412 13 Copyright 2006 2012 MagOasis LLC All rights re aTa O a ai MagOasis Magsimus Deluxe User Manual for use with Microsoft Windows Copyright 2006 2011 John Oti MagOasis LLC All rights reserved This manual as well as the software described in it is furnished under license and may only be used in accordance with the terms of such license The license provisions are described at the end of this user manual Please refer to it if you have any questions MagOasis has reviewed this manual thoroughly in order to make it an easy to use guide for the Magsimus Deluxe software All statements technical information and recommendations in this manual are believed to be reliable but the accuracy and completeness thereof are not guaranteed or warranted and they are not intended to be nor should they be understood to be representations or warranties concerning the products described All commercial names of equipment and software referred to in these pages are trademarks of their respective owners Chapter 1 Introduction 00 0c eee eee 7 Chapter 2 Getting started 0 00 2 ee 11 System requirements 0000 cee ee eee hh hee 11 INStANANONM eer P 11 Magsimus Deluxe software package 0000 e ee eee eee 11 Web installation es
85. No 1 Ao 25 562 09 al la 25 1 where n is a pre factor for coupling of the j th component that the user can explicitly specify in the target component s property editor dialog box Nom is the number of components that are GMR coupled to the target component and abs J a max abs 1 Aa is the current flowing in the j th component normalized by the maximum current among the GMR coupled components and the target component m is the unit vector of the target and m is a current distribution weighted average of the unit magnetization vectors of the points compu tational cells the j th component expressed in the frame of reference of the target component for which Ao is being computed Thus m depends also on the detail of the electrical current distribution within the j th component It is in general of less than unit magnitude The factor a simulates current shunting effects that cause coupled components to contribute towards the resulting GMR of the target component in proportion to the currents they carry Daughton 1997 The nj pre factor is a GMR ratio for the coupling between the target and a neighbor and may be estimated from experimentally measured GMR transfer curves Using standard integral field techniques the variation in the local conductivity values of a component is used in conjunction with its computed current density distribution to calculate the resulting conduc tances due to giant magnetoresist
86. RUPTION LOSS OF BUSINESS INFORMATION OR OTHER COMMERCIAL OR PECUNIARY LOSS ANY CONSEQUENTIAL SPECIAL OR INCIDENTAL DAMAGE OR ANY OTHER PERSON OR ENTITY AS A RESULT OF YOUR USE OR INABILITY TO USE THE SOFTWARE OR DOCUMENTATION EVEN IF MAGOASIS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THIS LIMITATION MAY NOT APPLY TO YOUR RESTRICTED RIGHTS This SOFTWARE and DOCUMENTATION are Commercial Computer Software provided with RESTRICTED RIGHTS under Federal Acquisition Regulations and agency supplements to them Use duplication or disclosure by the Government its agencies or instru mentalities is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause at DFAR 252 227 7013 or subparagraphs c 1 and 2 of the Commercial Computer Software Restricted Rights Clause at 48 CFR 52 227 19 as applicable or successor provisions Manufacturer is MagOasis LLC P O Box 7472 Tyler Texas 75711 USA General Provisions Licensee may not assign this license except to a subsidiary or parent company of the Licensee Should any act of the Licensee purport to create a claim lien or encumbrance on any SOFWARE such claim lien or encumbrance shall be void All provi sions regarding warranty liability and limits thereon and protection of proprietary rights shall survive te
87. Show Grid When selected displays grid lines for the parametric plot Show Axes When selected displays the coordinate axes of the surface plot The cut points of a surface cut displayed in the parametric plot box are plotted in the Cut trace box The X Y Y Z and X Z options in the area under the parametric plot box are used to make the orientation of the cutting plane lie parallel to the corresponding coordinate planes The position of the cutting plane is varied by moving the s ider or by entering a value in the box to the right of the slider To the right of this input box is a label X Y or Z showing the current variable represented by the cutting plane position During a simulation the output graph for the current values of the param eters is traced out in the box under the Cut trace box Clicking and holding down the left mouse button anywhere in this box or in the Cut trace box displays on the window caption the coordinates of the mouse pointer expressed in the plot coordinates of the boxes A complete simulation for a specific parameter values is called a scan At the conclusion of a scan its graph is moved into the surface plot shown in the Parametric plot box Clicking the right mouse button anywhere in the plot area displays a floating menu that can be used to store the plotted data to file send its graph to a printer or modify the drawing attributes of the plot box colors and line widths of curves and axes and backgrou
88. Solver 72 static solver 19 status bar 104 Stochastic Thermal Model 93 Stop button in main program upper toolbar 110 in Simulation area of main program s upper toolbar 110 Summary button in Material library dialog 220 SUPER USER license access type in About dialog box 107 surface charge distribution 63 Surface mesh divisions frame in Geometric tab of Magnetic Shield specification dialog 199 surface mesh panels 199 Surface plots 230 surface pole density 73 surface slices 230 System 77 130 system problem coordinates XYZ 57 System circuit diagram box in Electrical Circuit tab of System specification dialog 168 System component hierarchy 55 System Design Manager 20 29 System Display pane 158 205 System display toolbar 110 146 system electrical circuit 57 system hierarchy See System component hierarchy system object 55 System report 158 System requirements 11 System Specification dialog box 20 System specification dialog box 77 System specification window Calculation tab 163 Electrical Circuit tab 167 General tab 162 Units tab 169 System Specifications Main program menu item 106 System Structure list 24 27 29 30 35 System structure list in Importing components window 225 System thermal model in Calculation control tab dialog of Environment Settings dialog 120 System view box in Importing components window 225 System View window 103 129 System view window 130 131 S
89. Value field is ignored Direction of current in component Specifies the direction of electrical current flow through the component Calculate surface charges for all faces Checking this box indicates that induced surface charges are to be calculated for all sides of the shield Faces to turn off area In this area the user can turn off the calculation of surface charges for selected faces of the shield These selections are ignored indeed the area is disabled if the box Calculate surface charges for all faces was checked The designations for the faces are given relative to a frontal view of the shield in its coordinate system lst U V face Checking this box disables the top face of the shield 2nd U V face Checking this box disables the bottom face of the shield 1st U W face Checking this box disables the front face of the shield 2nd U V face Checking this box disables the back face of the shield lst V W face Checking this box disables the left face of the shield 2nd V W face Checking this box disables the right face of the shield Interact with all system components Checking this box indicates that the shield can interact with all components of the system Components area Ifthe box Interact with all system components is un checked then the list in this area will contain only those components that the shield can interact with Add Pressing this button adds a component to the interaction list Delete Pressi
90. WARE may be used on a backup computer or replacement computer when a software access key is used Licensee must not service or otherwise tamper with the normal opera tions of the software access key Licensee may use the SOFTWARE only for its internal operations by its own employees or those of its subsidiaries or parent company Licensee may not make the SOFTWARE available for use by third parties Licensee must discontinue using the SOFTWARE in its normal mode of operation after the date of expiration of the license as indicated in the About dialog box of the Help menu of the main program window unless authorized otherwise explicitly by written permission of MagOasis Termination MagOasis may terminate this license by written notice to Licensee if Licensee 1 breaches any material term of this agreement 2 fails to pay the amount charged for this license within 2 days after delivery or 3 ceases conducting business in the normal course Licensee may terminate this agreement at any time by written notice to MagOasis Licensee shall not be entitled to any refund if this agreement is termi nated Upon termination Licensee shall return all copies of the SOFTWARE and DOCUMENTATION Limited Warranty limitation of remedies For a period of thirty 30 days from delivery MagOasis warrants that each SOFTWARE will conform in all material respects to the description of such SOFTWARE s operation in the DOCUMENTATION In the event that the SOFTWAR
91. X Y selected from the Data to filter box Below this box depending on the filter type selection one or two threshold harmonic input boxes min Harmonic and ormax Harmonic are provided Spectral filter settings Current maximum harmonic in this data set is 54 Filter type Data to filter C Low pass x x Min Harmonic e Max Harmonic C High pass 35 Cancel Help Fig 8 13 Spectral filter settings dialog box Plot settings dialog box The dialog box that is used to simultaneously specify plot attributes and data transformation for 2 D curve windows is shown in Fig 8 14 This dialog box is usually displayed my making the selection x in the short cut menu displayed after right clicking the mouse window anywhere in the plot area of a 2 D plot window This dialog box has the following functionality Plot settings Axes attributes Scaling type Auto C Manual Major tic marks Plot type C Normal C Integral C Derivative Y min 10 T p Ymax fo Minor tic marks C X Fourier Spectrum C Y Fourier Spectrum Spectral data Real part Settings Colors Background C Foreground Data markers Show data markers Line thickness Axes 2 v Curve 1 i Marker symbol Along x 0 Circle v Along 0 Along X 3 v Along IV Use solid symbol Marker size 1 OK Cancel Help Fig 8 14 Plot settings dialog box
92. a tion vectors Show electrical circuits Tums on off the display of defined elec trical circuits Show magnetic anisotropy Axes Turns on off the display of defined magnetic anisotropy vectors Show current density vectors Turns on off the display of current density vectors of design components Show coordinate axes Selecting this item displays a floating menu whose items can be used as follows to display on the System View window the various Cartesian coordinate frames axes of the design System Axes displays the system coordinate frame Group Axes displays the coordinate frame of groups Component Axes shows the coordinate axes of all com ponents elements arrays and probes of the system Show A11 shows all coordinate axes of the system groups and components Hide A11 hides all coordinate axes Show Component outlines Turns on off the display of the outlines of the components of the system Show Component Labels Selecting this item causes labels of design components to be displayed in the System View window Groups are labeled n where n is the group number the m th component of the n th group is labeled n m Hide A11 Causes all of the above attributes to become hidden in the System View window Set selected component display attributes This menu item is enabled if a component is selected in the system display pane Displays a submenu for specifying design display attributes for the component s
93. a input specifications and generated output data will be inde pendent of time During quasi static calculations applied fields are dependent on time while magnetization is time independent This approximates condi tions in which the magnetization changes in the material occur at a much faster rate than the changes in magnetic field In this case input specifications and generated outputs are dependent on time however the transient solution states are independent of time Magnetization and field are both time dependent in dynamic simulations The non equilibrium magnetization states are also time dependent in dynamic calculations All input specifications and outputs are time dependent in this case The magnetization of an element or cell is mod eled by the Landau lifshitz and Landau Lifshitz Gilbert equations Different forms of these equations are used for the different calculation methods Refer to the User Manual for more details Solver Iteration Control frame Use default method Use user defined method options Applies only to Dynamic calculations These choices allow the user to specify whether dynamic calculations are to be carried out according to the default program solution technique or in consideration of certain user imposed constraints Internally dynamic calculations are carried out by means of a self correcting and variable step size differential equation integrator The default method uses any number of generally varyi
94. al Settings dialog 114 Enable recording to external disk files for new designs option in General Option tab dialog of Environmental Settings dialog 114 Enable simulation check pointing for new designs option in General Option tab dialog of Environmental Settings dialog 114 Enable SMT minority carrier reflection checkbox in Magnetoresistance tab of Array specification dialog 190 Enable spin momentum transfer SMT effects with coupled components in Magnetoresistance tab of Array specification dialog 189 End in Rotation external field definition dialog box 156 End box in parametric output window 214 End value box 48 in Parametric simulation tab 153 energy densities 230 Energy density output of 83 energy loss damping mechanisms 71 energy well 92 Environment preferences 53 Environment Settings Calculation control tab 119 Color attributes tab 118 General Options tab 113 Start up Units tab 116 Environment settings Main program menu item 106 environment settings 112 227 equilibrium 70 equilibrium magnetic state 68 70 163 Equilibrium iteration count in status bar panel of main program window 111 equilibrium states 167 Equilibrium write threshold box job control action in Background job monitor 127 Euxine Technologies 242 Exchange 69 228 coupling field 60 element magnetic properties 60 Exchange A param within array in Exchange Coupling tab of Array specification dialog 187 exchan
95. al effective field 71 Total field duration box in Loop external field definition dialog box 155 in Rotation external field definition dialog box 156 Track M rotation angle box in Calculation tab dialog of System specification dialog 166 transient 70 transient states 167 translation motion 8 Translation velocity frame in Motion tab of the Group specification dialog 175 Translation velocity in system frame 39 40 Tsang C 89 97 Tunnel Junction Models 94 Tutorial 2 Parametric simulation example 45 Type frame 46 magnetic anisotropy in Magnetic Anisotropy tab of Array specification dialog 185 U U origin in Geometric tab of Array specification dialog 181 Origin in Geometric tab of Magnetic Shield specification dialog 198 Origin in Geometric tab of Probe specification dialog 196 U box 25 30 uncompensated magnetic poles 75 Undo button 28 in main program lower toolbar 148 Uniaxial anisotropy 228 uniaxial magnetic anisotropy field 80 Uniaxial option 46 magnetic anisotropy in Magnetic Anisotropy tab of Array specification dialog 185 unidirectional anisotropy 79 Uninstall Magsimus icon 13 United States 245 247 units 53 Units box in dialog for specifying output data for a group 207 nnel Junctions 68 SB port 14 se as group input check box in Electrical Circuit tab of group specification dialog 173 cae Use as group output check box in Electrical Circuit tab of group specification dialog 173 Use cust
96. alog of Environment Settings dialog 118 Color button 24 in Lines and Colors tab of Array specification dialog 191 in Lines and Colors tab of magnetic shield specification dialog box 202 in Lines and Colors tab of Probe specification dialog 197 Colors frame in Plot settings dialog box 212 Company name Magsimus About dialog box 107 Component list in Parametric simulation tab 153 Component origin in group coordinate frame iin option in Geometric tab of Element specification dialog 25 in Geometric tab of Array specification dialog 181 in Geometric tab of Magnetic Shield specification dialog 198 Component origin in group coordinate system in Geometric tab of Probe specification dialog 196 Component report 158 Components area in Electromagnetic tab of Magnetic Shield specification dialog 200 Components list in Magnetoresistance tab of Array specification dialog 190 inter element coupling in Exchange Coupling tab of Array specification dialog 187 Computed time in status bar panel of main program window 111 computer workstation 13 Conductivity in Electromagnetic tab of Magnetic Shield specification dialog 200 conductivity 7 65 Conductivity box in Electromagnetic tab of Array specification dialog 183 Connection to other components frame 35 Connections to other components area in Electrical Circuit tab of group specification dialog 173 Constant current option in Electrical Circuit tab of group specification dialog 173 in Electrical Ci
97. als carefully before proceeding further with the software The narrative will often be wordy to ensure that the described concepts are well understood The user who patiently follows the material in its entirety will derive the maximum benefit from the tutorials The Magsimus user interface Magsimus sports a thoughtfully designed user interface to assure a friendly and intuitive modeling experience for the user This is brought about by simplifying access to the program s comprehensive range of features The major parts of the user interface are the main program window the backdrop and the System view windows that is contained in it Fig 3 1 The main program window consists of the program menus and the following tool bars 1 The Recording and Simulation tool bar is used for the initiation and playback of simulation recordings and for the initiation of a simulation by pressing the Run button 2 The system display tool bar is used for interactive manipulation of the three dimensional display of the design in the System view window The System view window displays a three dimensional rendering of the system design and contains the following areas 3 The Design Manager no 2 in Fig 3 1a is the starting point for building a Magsimus design A typical Magsimus design session entails the adding of new design groups the modification of existing groups and the population of the groups with design primitives groups single elements
98. ance for the system components From these the output conductances can be computed for the underlying design group circuits The GMR ratio of a component or group of conductance G is given by 4 _ 27 R leur G max where Gmax is the maximum conductance the conductance of the component or group when uniformly magnetized saturated in an arbitrary direction in space The current direction input which the user can specify for a component determines a component s electrical input and output nodes relative to which the conductance is defined For a group which may have a component composition and structure of any complexity the conduc tance is calculated using the electrical current and voltage values of a pre determined group output component The user can optionally specify this output component If an output component is not defined by the user then the last electrically connectable component in the group design hierarchy is used as this component Similarly if a group input component were not specified it is assumed to be the first electrically connectable component in the group s design hierarchy Above discussion presumes that there is current flowing in all the relevant parts of the system A GMR output will be generated for a group and its components even when no circuit with current sources has been specified for them In this case a circuit with a fictitious unit current source is employed in computing the GMR response
99. and M is its saturation magnetization The exchange coupling between a pair of components is non reciprocal This means that the field by which the i th component couples to the j th component is not necessarily the field by which the j th component couples with the i th By default Magsimus offers the user the option of specifying exchange interaction inputs as a field H Alternatively the user may opt to specify exchange interactions by means of an exchange parameter A Zhu 1989 This can be done by making the appropriate selection in the Environment Settings dialog box see chapter 6 The exchange fields and parameters are related by the expression H 24 M d where d is the distance between the coupled objects This distance is calculated differ ently for various types of exchange coupling definitions in Magsimus for intra layer coupling among the cells of an array component d is the distance between the centers of adjacent coupled cells for inter component bulk coupling single single single array component or array array component couplings d is the distance between the geometric centers of both components for interface single array coupling d is the distance between the geometric centers of the single component and the interface layer of the array for interface array array coupling d is the distance between the geometric centers of the interface layers of both arrays The user has the option of excluding the
100. and appendices are organized as follows Chapter 2 The system requirements and software installation of Magsimus are described in this chapter Chapter 3 Detailed descriptions of two design examples aimed at acquainting the user with the features of Magsimus are presented in this chapter We recommend that the new user go through these examples first before proceeding further with the software Chapter 4 A formal discussion of the design objects and coordinate systems used by Magsimus is given in this chapter Chapter 5 The computational details of mathematical solvers and the data outputs generated by the software are described in this chapter Chapter 6 This is a reference chapter that describes the main program window and its user interface elements Chapter 7 This reference chapter presents a detailed description of the user interface elements of the System View window on which the design is displayed and the various means of interacting and applying fields to the system Chapter 8 This reference chapter describes the remaining user interface elements not treated in chapters 6 and 7 This includes the properties specification dialogs of design components mechanical motion electrical circuits and data output windows Appendix A Presents a summary of software features of Magsimus Appendix B A detailed listing of the output types of the design compo nents of Magsimus is given in this Appendix Appendix C Discusses th
101. anisotropy fields 0 0 00 c eee 79 Exchange interaction field 0 0 0 cect teas 80 Output data o4 ILIA DERI teeta a ee AREAS Teas A au 81 Iteration distance traveled and time llle 82 Magnetization and Magnetic Induction liliis 82 Energy density savas aoe ge le EE are Ral ERA EAR ee ER 83 Electrical current and voltage 0 2 0 tee 84 Giant magnetoresistance GMR 0 00 eee eee eee eee 84 Spin momemtum transfer SMT phenomenom 00 0 eee eee 87 Anisotropic magnetoresistance AMR llle eae 89 Magnetic Tunnel Junctions MTJ 0 0 2 0 II 90 MagneticfOrce CE 91 Thermal Modeling 2 0 ssec ea ee ee ee 92 Classic Thermal Model 0000 cece ett 93 Stochastic Thermal Model 0 00 cee ett 93 Tunnel Junction Models isslsieeeee naana 94 Simmons model es hoop pees SEA phe da Pw eg eee EE ee ee 95 Bibliography x ise e EORR yu RE ERR E Pad baad a ua Rad D Ry 96 Glossary of mathematical symbols lille eres 98 Chapter 6 Magsimus Reference Main program window 103 INTHODUCUION sa 2 ettet od ctt padece deed Bd aware bo wea eese 103 Main program window 1 0 m eae 104 Menus of the main program window llis 105 Upper tool bar of main program window Recording and Simulation launch tools 108 Lower tool bar of main program window System display tool bar 110 Magsimus status bar
102. aphs of the output data we defined previously will appear These windows have the captions 1 2 Current I mA Vs Iterations 2 1 Y component electrical current field Hley Oe Vs Iterations and 3 1 Magnetization along external field Mh emu cc Vs System external field amplitude HextA Oe Notice the group component convention for the outputs For example 1 2 refers to the second component of the first group and 3 1 refers to the first component of the third group The graphs of these outputs are traced out as the calculation progresses The graph windows may initially be minimized depending on the prevalent software environment settings Restore the plot windows from their minimized states if need be re size and position them where they are visible such as is done in Fig 3 2 Now you can observe the full simulation as the components of the design interact with each other By positioning the mouse pointer anywhere in the plot window pressing and holding down the left mouse button the coordinates in plot units of the location of the mouse pointer is displayed on the caption bar at the top of the window Clicking with the right mouse button on a plot window launches a floating menu that can be used to store the plotted data to file send its graph to a printer or generate plots of other mathematical transformations of the data Remarks For a static calculation such as this one the duration of defined electric current
103. at start of simulation C Exchange parameter A w Preserve array layout patterns between specs edits Always flag new designs for background job submission V Automatically scale new output curve plots Plot data markers for new output curve plots Show license activation dialog during start up and after license failure softkey only v Enable the showing group level extemal field panel for all new design groups r Default input types for geometric origins Group Relative to the previous group T Component Relative to the previous component OK Cancel Help Fig 6 7a General Options tab of the Environment Settings dialog General environment settings are specified here Fig 6 7a Some of these settings are used as default settings for newly created designs They do not apply to pre existing designs loaded into Magsimus from external files Other settings under this tab affect the operational environment of Magsimus Replay available recordings upon design load option Checking this box will cause the immediate play back of any stored simulation recordings in the loaded design Enable recording to external disk files for new designs option Checking this box will ensure that all new designs will be re configured to save simulation recording data to a external files Show tip of the day at start up option Checking this box will result in a tip of the day being displayed whenever Magsimus is star
104. ate systems of Magsimus Group and component options This selection points to which of the selected components in the System display pane the changes in angular coordinates will apply to When a component is selected in the System display pane its parent group is automatically selected as well Azimuth angle Specifies the azimuth angle of the selected item This entry can also be modified using the scroll bar beneath it Polar angle Specifies the polar angle of the selected item This entry can also be modified using the scroll bar beneath it External field and simulation specifications External fields of virtually any complexity can be applied to Magsimus designs Here we describe the means for defining external fields that are to be applied to a design and the specification of the parameter ranges for parametric simulations The dialog box for accomplishing this is displayed by pressing the Edit button of the External field controls This dialog box is shown in Fig 7 11 External field specs tab E External field and simulation specifications for system Select field scope System level Group level Zi Static calculation r External field specs Y System parametric simulation specs Field Type Min field Qe 300 Max field De 300 Loop Es Field leg 1 Polar angle Deg 90 Azimuth angle Deg 0 cU Add No of data points 100 Delete Clone OK Cancel Help
105. ating sub menu item of 2 D curve window 211 Fourier component in Plot settings dialog box 212 Import button in Importing components window 226 Import component menu in integrated Design Manager 135 Import component s button in System Design Manager 224 Import external components button in integrated Design Manager 133 Importing components 224 importing components 52 Inch in 116 Include self fields in the calculation of charge map in Calculation Controls tab of Magnetic Shield specification dialog box 201 induced poles 73 infinite permeability 63 infinitely damped system 72 infinitely damped torque equations 228 initial phase 68 Inomata K 96 Input type box in Geometric tab of Array specification dialog 181 in Geometric tab of Element specification dialog 25 in Geometric tab of Group specification dialog 30 31 33 in Geometric tab of Probe specification dialog 30 196 in Geometry tab of Group specification dialog 171 input output options in Electrical contact properties dialog box 177 Input current axis in Electrical contact properties dialog box 177 Input current axis list in Electromagnetic tab of Array specification dialog 183 Insert component menu in integrated Design Manager 135 Installation and Use 243 Integral as output curve data transformation 82 floating sub menu item of 2 D curve window 210 plot type option in Plot settings dialog box 212 integrated Design Manager 131 Interacting objec
106. ation environments to your taste Rich choice of computational units Conveniently select from a wide range of electromagnetic time length and rate units to meet about every need Context sensitive online help Instant design reports Up to the moment updates of the properties of the system groups and individ ual components Materials library Native and user defined archive Solvers Accurate state of the art models with extensive solver control features Dynamic calculations Landau Lifschitz and Landau Lifschitz Gilbert equations Static and quasi static calculations Solution of infinitely damped torque equations Pseudo soft magnet model Magnetization of pseudo soft magnets can change in both magnitude and direction 3 D Magnetic Shield Model Design primitives Material types Normal magnets non magnets permanent magnets pseudo soft magnets magnetic shields and probes Component types Individual and array components Importation of external design components Create reusable components and then import them into other designs Full micromagnetic interactions Magnetostatics Exchange Exchange coupling between components Inter cell exchange coupling in arrays Magnetocrystalline magnetic anisotropy Uniaxial and pinning anisotropies Complex anisotropies from combination of simpler ones External magnetic fields External field sources Fields produced by electrical currents Magnetoresistive effects
107. be within a group is given by its displacement from the previous component of the group measured in the group coordinate frame If the probe is the first component of the group then the specified displacement is relative to the group coordinate origin Field Array A field array is a three dimensional rectangular array of points for visualizing a vector field region It does not represent a physical material object but a construct of points The field components that can be visualized are the magnetostatic fields produced by the polarization of magnetized objects as well as magnetic fields produced by currents flowing in the system The geometric properties of field arrays are the same as those of the material array described above The field points coincide with the centers of the array cells in this case Chapter 5 Mathematical Theory In this chapter we discuss the mathematical formulation of Magsimus and the calculation of its data outputs All field equations are written in SI units The chapter concludes with a Bibliography section listing cited references and a glossary of mathematical symbols introduced in the chapter Electrical circuits Overview Magsimus supports the definition of electrical circuits for a system and its components It uses a linear nodal network analysis model to calculate the electrical responses of the system Balabanian and Seshu 1963 In this approach each design component is treated as a passive ele
108. bility and the Recording Playback Carousel that were described above are examples of such tools Brief introductions of a selection of other tools now follow More detailed descriptions of each tool can be found in the appropriate sections of Chapters 6 and 7 of this manual Batch Job Manager The Batch Job Manager provides a means for scheduling and running a sequence of simulations In a typical scenario the user collates separately created design in the Batch Job Manager and then executes them in sequence either directly in the loaded Magsimus environment or as background processes Each simulation is saved to a specified desti nation file when completed This feature is ideal for unattended running of a batch of simulations during after office hours An effective use of this capability is for chaining a sequence of related simulations For example the output of one simulation may be used as the input for the next simulation The job specifications constitute a template that can be saved to file and re used in separate Magsimus sessions The job of the Batch Job Manager is also performed by the external utility application MagJob Importing Components Magsimus offers a means of importing external designs into one that is currently loaded This promotes the reusing of proven components in other designs This feature is well suited for creating complicated systems out of simpler ones The user can separately optimize the simpler desig
109. by summing together the contributions from all shield components of the system N is number of shields and o is point surface charge density The contribution of each shield in turn is found as a surface integral of the contributions of the induced poles of its surface mesh panels In 13 Sj denotes panel area for the j th shield and G 1s the appropriate Green s function for the interaction between a surface panel and an element Magnetostatic truncation region The long range nature of magnetostatic interaction fields typically makes them the most time consuming field terms to compute during a simulation For a system consisting of N interacting magnetic objects counting single magnetic components array cells and the panels of the magnetic shield surface meshes the calculation of magnetostatic inter action fields can asymptotically be of the order of w this fact can be expressed more formally using the notation o Computational throughput can therefore be adversely affected by a large v To minimize computation time for magnetostatic interactions Magsimus gives the user the option of reducing the effective v in the calculations The assumption is made that the impact on the magnetic response of a component by the magnetostatic interactions of other components of the system sufficiently distant from it can be neglected Thus the number of objects which the component can interact with is reduced to the number that lie within a mag
110. c force FX Y component magnetic force FY Z component magnetic force FZ Magnetic force Appendix B Magsimus files Magsimus depends on a variety of files for its normal operation These files are described in this appendix All files formats are ASCII Design files mus files These files combine all the necessary specification information for Magsimus designs and all the outputs and recorded design states generated during simulations Designs are saved to these files by clicking the main program menus File gt Save or File gt Save As Existing designs can be loaded into the software by clicking the File gt Open menu Magsimus license file MUSCII cli This file contains the license information for Magsimus The license privileges extended by ET to the user are encapsulated in this file The license file resides in the application directory of the software Magsimus licenses are discussed in Chapter 2 Getting Started Recording Carousel files crs files These files hold information about recording carousels The carousels allow a set of design files containing recorded simulations the carousel items to be played back one after another in a prescribed sequence Batch Job files mbat files These files hold information about batch job sequences that are created using the Batch Job Manager Material database file Matdb ddd This file stores the material library used by Magsimus It resides in the Data
111. ce tab of Array specification dialog 189 Giant Magneto Resistance Devices 96 Gilbert damping factor 71 Gilbert precession factor 71 global internet 107 Glue Un Glue group components System display pane action menu 145 GMR 84 coupling 85 GMR transfer curves 86 Graph re plot pitch box in Calculation tab dialog of System specification dialog 166 graphical user interface GUI 7 Green s function 75 77 Group and component options in Moving Component dialog box 160 in Rotating Component dialog box 149 Group button 29 Group Circuit diagram box 35 Group circuit diagram box 35 37 in Electrical Circuit tab of group specification dialog 174 in Electrical circuit tab of Group specification dialog 172 group component coordinates uvw 57 group coordinates UVW 57 group electrical circuit 35 57 Group list in Magnetoresistance tab of Array specification dialog 190 in Parametric simulation tab 153 inter element coupling in Exchange Coupling tab of Array specification dialog 187 Group option 47 Group origin in system coordinate frame 31 33 in Geometric tab of Group specification dialog 30 in Geometry tab of Group specification dialog 171 Group report 158 Group Specification dialog Electrical Circuit tab 171 Geometry tab 170 Group Specification dialog box 170 Group specification dialog box 30 32 Group level option in Select field scope frame 41 Group level option in system external field specification
112. changes in time occur as magnetic fields are swept between equilibrium magnetic states The calculation method can be specified at the System Specification dialog box which is reachable from the System Design Manager described below Solution methods are discussed in detail in Chapter 5 Units Magsimus offers a rich choice of calculation units to fit different modeling requirements These units express electromagnetic time length and rate quantities used in a design Units are specified in the System Specification dialog box For our example magnetic quantities fields and magnetization will be expressed in CGS units In CGS units field is expressed in Oe Oesterd and magnetization is expressed in emu cc electromagnetic unit per cubic centimeter An alternate system of magnetic units available in the software is the SI units Field and magne tization are both expressed in A m Ampere per meter in SI units The coarser unit kA m 1000 A m is used in the dialog boxes Length will be expressed in nm nanometers throughout this tutorial System Design Manager Start Magsimus The screen shown in Fig 3 3 is displayed The main program window the one with the caption Magsimus Deluxe Untitled mus contains the System View window with caption New problem The System View window contains an integrated Design Manager which is used to define and maintain the design The Design Manager consists of two parts a tool bar of action b
113. ck many recordings at once in sequence The Recording tools provide the means for recording of data during simulations and for playing them back Each recorded snapshot of the system is called a frame In addition to using the recording buttons a recording that is being played back can be paused or terminated by pressing the Pause or Stop buttons of the Simulation area 1 Record Pressing this button during a simulation initiates recording of the simulation up until the button 1s again pressed or the simulation ends or is terminated by the user Recording takes place in the on state of the Record button the caption of the record button is black in color and reads Can for cancel In the off state the color of the caption reverts back to red and the caption reads Rec for record Separate portions of a simulation can be recorded by turning the record button on and off during those portions 2 Forward play Pressing this button plays back recorded data so that the simulation is retraced in its normal forward direction 3 Reverse play Pressing this button plays back recorded data so that the simulation is retraced reverse wise 4 Pause Pressing this button pauses the playback of the recorded data 5 Stop Pressing this button terminates the playback of the recorded data 6 Replay Go to Pressing this button displays an input box for entering a specific recorded frame to load 7 Replay Mode Specifies methods for playing
114. cons Use the Uninstall Magsimus icon if you need to remove the software from your computer Magsimus licensing A new Magsimus installation operates by default in demonstration or demo mode This is a restricted mode of operation The user needs to operate the program in its normal mode in order to derive its full benefits by installing an MagOasis supplied license file WUSLic cli All the design creation and manipulation capabilities that are available for the normal mode of operation are also available for the demo mode New designs can be created and loaded designs can be modified However designs cannot be saved to file and calculations cannot be performed on them The demo mode is useful for evaluating the capabil ities of Magsimus and for developing familiarity with its controls prior to committing to acquiring a normal license If Magsimus encounters diffi culties in verifying a license during normal operations it falls back to its demo mode of operation MagOasis licenses are classified as soft or hard key see below depending on their access method Each license has a duration associated with it beyond which the software defaults to the demo mode of operation This may be for a duration of few months one year or an indefinite duration permanent license The latest information on the duration of Magsimus licenses and pricing information are available at the MagOasis web page An expired license can be renewed by acquiring
115. ct definition swatch Within the swatch a rectangular line grid schematically represents the array cells of the face for which the contact is being defined To define a contact tab click and hold down the left mouse button on a cell at one corner of the swatch Without releasing the mouse button drag the mouse to another corner of the rectangular region and release it A rubber band box is swept out as the mouse is dragged The area occupied by the contiguous cells that intersect the final rubber band box becomes the contact area for the component face A thick blue box is formed around the new contact region the new tab position is listed in the Panel box to the right of the swatch and a textual annotation of the end cells of the area is updated below the panel box this is the label located below the swatch that begins with X1 YI X2 Y2 Individual tabs can be selected from the Panel box A selected panel is displayed with a green outline in the swatch The contact area can be specified independently for input and output contact tabs Fig 8 5 shows a patterned array component and its electrical circuit with contact tabs on display Pressing the Delete button removes a panel selected in the Panel box Pressing the Reset swatch button removes all defined panels Note An electrical contact is always defined for a component that is part of the electrical circuit of the design For such components the solver provides a default contact
116. cted in the System structure list then right click the mouse in this box In the displayed popup menu select the item Add gt Element An Element specification dialog for the new component you are creating is displayed Make the following data entries under the indicated tabs 1 Geometry tab In the frame Linear dimensions along coordinate axes nm enter Length Lu 200 Width Lv 200 Thickness Lw 700 In the frame Component origin in group coordinate frame nm first make sure that the option Relative to previous component is selected in the Input type box then enter U 0 V 0 w 500 Note The selection made in the Input type box above determines how the coordinate inputs will be interpreted In the current example the inputs will represent displacement from a prior component if any in the parent group In the frame Angular orientation coordinates within group Deg enter Azimuthal 45 Polar 30 2 Electromagnetic tab Magnet type Select Non Magnet from drop down list 3 Data Output tab Fig 3 6 Specify output for the element as follows Create a new data set by pressing the New button The created data set has default X and Y outputs of the type Iteration The Iteration output is the iterative count during calculations it acts as a ticker that measures the progress of the calculation Other types of outputs may be defined The outputs are organized by categories listed in the Data Category box
117. cussion of magnetostatic interaction fields Reset surface charges at start of calculations Checking this box results causes the surface charge value to be set every where to zero at the start of a calculation Freeze surface charges during calculations Checking this box will cause the pre existing surface charges on the shield to remain unchanged during a calculation Lines and Colors tab iG Magnetic Shield Specification 1 1 Field shield cover User defined Params Data Output Calculation Control Geometry Lines and Colors Shield outline A C Current density vector arrow Line Thickness 2 X OK Cancel Help Fig 8 9d Lines and Colors tab of Magnetic Shield specification dialog The appearance of the outline of a shield and the arrow of its current density vector when displayed in the System View window is modified here by specifying line colors and line widths Outline and Current density vector arrow options Selecting either option allows its corresponding attributes to be modified Color Pressing this button displays a dialog for editing the line color The currently selected color is displayed at the swatch to the left of this button Line thickness The line thickness for drawing the shield is specified here either by typing in a value in this space or by selecting a value from the drop down list A sample of the currently specified line is displayed at the swatch to the left of the input fie
118. d Design Manager 2 External field controls 3 A system display pane Integrated Design Manager The integrated Design Manager is the main interface for building a Magsimus design A typical design session in Magsimus involves the addition of new groups to a design the modification of existing groups and the population of the groups with design primitives elements arrays probes and shields the definition of mechanical motions electrical circuits group and component level data output etc The Design Manager is the main interface for building a design In this section we give a detailed description of it and the other design management dialogs reachable from the design manager See Chapter 4 Design Components and Coordinate Frame for a full discussion of the system hierarchy Action toolbar Normal magnet Pseudo soft magnet Permanent magnet System structure Non magnet box Magnetic shield Hg Array of normal magnetic cells Array of pseudo soft magnetic cells E Array of permanent magnetic cells mm Array of non magnetic cells Group with just one component H New Elementi Fig 7 2 Magsimus integrated Design Manager and its parts The Action tool bar consists of the following buttons 1 Add group 2 Add element 3 Add array 4 Add magnetic Shield 5 Add probe 6 Add fi7 Import external components Fig 7 2 provides a closer look at the Design Manager This tool consists of two areas as shown in the f
119. d its applications see for example Hunt 1971 Tsang and Decker 1984 Unlike GMR it involves only the magnetization of the component The conductivity of a component single element or array cell changes by virtue of the AMR as follows 2 ot o 0 t Aot sin 0 Er 31 max where 0 is the angle between the directions of magnetization and current in the component i is the magnitude of current in the cell ipay is the maximum current magnitude of the cells is a measure of the fraction of the component s current flowing in the cell As in the case of GMR the cell conductivities which may change due to AMR are used in conjunction with a component s current density distri bution to calculate its conductance The AMR of a component or group is calculated from the expression G G AR EE min 32 R IAMR G min where G is the conductance of the device and G is its minimum conductance calculated by setting the cell conductivities to their intrinsic values og everywhere In the case when no current flows in the device the AMR response is calculated as with the GMR model using a circuit which is supplied by a fictitious unit current source Magnetic Tunnel Junctions MTJ Magnetic tunnel junctions MTJ have become subjects of much recent interest due to their role in the development of next generation spintronic devices Hirota et al 2002 A variety of phenomenological models are implemented in Magsimus D
120. d surrounds it with a yellow box Source Group Drop down list containing the connectable groups of the system Selecting a group from this list defines it as a source group Current source area The type of current sources connected to a source group component are specified in this area A current source has two terminals positive and negative The positive terminal is connected to the positive terminal of the source component while negative terminal can be connected to the negative terminal of the source component or another circuit component None Specifies that a current source is not connected to the source component Constant current Specifies that a constant current source is connected to the source element The input box to the right is used to enter the output current of the current source in milliamperes Custom current profile Specifies that a variable current profile is connected to the element Clicking the box to the right displays a window for specifying custom current profiles Source exit component Specifies the component whose negative terminal is connected to the defined current source Destination Group Drop down list containing the connectable groups of the system Selecting a group from this list defines it as a desti nation group Below the Destination Group is a framed area containing a set of check boxes for accomplishing the connection of source and destination groups Lines connecting the ch
121. d systemati cally Magsimus returns the system to its original state prior to updating the parameter values The process of varying a parameter is called sweeping of the parameter Magsimus provides an interface for speci fying the design parameters to sweep and the range over which they are to be varied If data outputs are specified the family of curves produced for each output during a calculation is presented as a surface plot In this example we will subject a magnetic cube that is characterized by a uniaxial magnetic anisotropy to an external field loop whose direction is varied We will obtain as output the M H curve for this system as a function of external field direction Run a new instance of Magsimus or close down the current design and begin a new one by selecting the File gt New Problem menu item in the main program window In the later case if the loaded design has not been saved since the last time changes were made to it you are prompted to first save it before proceeding We add a cubic element to the one group New Groupl that was automatically created at the start of the new design Click the Element button of the Design Manager to display the Element Specification dialog Specify the following data inputs under the indicated tabs l Magnetic Anisotropy tab Create a new anisotropy definition by pressing the Define New button Enter the following inputs In the frame Type select the option Uniaxial Field Oe
122. data input areas are organized under different tabs in this window Geometry Electromagnetic Exchange coupling tabs etc Take some time to familiarize yourself with the inputs of the various tabs Pressing the Help button El Element Specification 1 1 New Element1 E Lines and Colors User defined Params Data Output Stimuli sources Electromagnetic 2 Magnetic Anisotropy Exchange Coupling Magnetoresistance Component origin in group coordinate frame nm Linear dimensions along coordinate axes nm Input type Relative to the previous component Length Lu po u Jo Width Lv 500 g Thickness Lw 500 w o Angular orientation coordinates within group Deg Azimuthal 0 Polar 0 OK Cancel Help Fig 3 4 Element specification window displays help information for the currently selected tab Note Online help access such as this one is readily available by pressing appropriate help buttons located throughout the software All online help are context sensitive which means that help infor mation pertaining only to the currently displayed dialog box or window is displayed whenever its help button is pressed Enter the following data for the element under the indicated tabs 1 Geometry tab In the frame Linear dimensions along coordinate axes nm enter Length Lu 1000 Width Lv 500 Thickness Lw 200 2 Electromagnetic tab Magnet type Select Non Magnet from drop
123. de are reflected in the field vector drawn in the field display pane Azimuth Displays and specifies the azimuth orientation of the active field The azimuth angle is reflected in the position of the scroll bar below this data area The azimuth angle can also be changed by manually changing the scroll bar position Changes in the applied field due to a change in the azimuth angle are reflected in the field vector drawn in the field display pane Polar Displays and specifies the polar orientation of the active field The polar angle is reflected in the position of the scroll bar below this data area The polar angle can also be changed by manually changing the scroll bar position Changes in the applied field due to a change in the polar angle are reflected in the field vector drawn in the field display pane System display pane The System display pane Fig 7 5 is where a three dimensional pictorial view of the design is displayed The pane is continuously updated as components are added to or removed from the system and as the system is modified in other ways The user can modify the displayed design directly with the mouse or can use the System display tool bar in the main program window to interact with and display different views of the system as well as modify its properties The System display tool bar which was introduced briefly in Chapter 6 is described in detail below A popup menu for modifying further the design and the way that
124. definition than group electrical circuits The latter specifies the electrical connections of components making up the group while the former specifies the connection of groups in a system circuit For a group to be connected in the system circuit it must contain at least one electrically connectable element i e non probe components and at least one of those components must have been designated a group input or group output component The positive terminal of a group in the system circuit is the positive terminal of the group s component that represents the group s input in the system circuit Similarly the groups negative terminal is the negative terminal of the group s output component Any two components that are to be connected to each other are arbitrarily classified as either source or destination components and corresponding areas of the window are used to specify their circuit properties For additional information on the system electrical circuit see Chapter 4 Design components and coordinate frames System circuit diagram Displays a schematic of the system electrical circuit The diagram is continually updated as the circuit is modified Each component is displayed as a rectangular box in this area Clicking once on a displayed component with the left mouse button selects it as the source component and surrounds it with a green box Clicking with the right mouse button selects the component as a desti nation component an
125. dialog 150 gyro magnetic constant 61 gyromagnetic ratio 71 Gyro magnetic ratio box in Calculation Control tab of Array specification dialog 193 H HARD KEY license access type in About dialog box 107 hard key 107 Hard Key license 14 hard key license 13 Hardware key 14 Harmonic 229 harmonic 68 Harmonics 66 harmonics 194 Harmonics currents 66 Help button in Batch Job Manager 125 in Recording playback Carousel 124 Help buttons 53 Hide All System display pane action menu 142 High pass option in Spectral filter settings dialog box 211 High pass X floating sub menu item of 2 D curve window 210 High pass X Y floating sub menu item of 2 D curve window 210 High pass Y floating sub menu item of 2 D curve window 210 Hirota 90 95 Hirota E 96 Horizontal box in Moving Component dialog box 160 HTTP protocol 107 Hunt R P 96 ideal shield 63 Ignore intra array magnetostatic interactions in Calculation Control tab of Array specification dialog 193 Ignore self demagnetizing fields of array cells in Calculation Control tab of Array specification dialog 193 Ignore u component of field check box in Calculation Control tab of Array specification dialog 193 Ignore v component of field check box in Calculation Control tab of Array specification dialog 193 Ignore w component of field check box in Calculation Control tab of Array specification dialog 193 image boundary conditions 73 Imaginary part flo
126. dividual harmonics sine wave components Mathematically this is given by the expression LV 3 A sin knt 0 1 n 1 where A is amplitude k is wave number T is fundamental period and 0 is initial phase of n th harmonic The software allows the user to specify the harmonics independently Tunnel Junctions Electrical tunnel junctions Wikipedia 2012 are special usually non conductive circuit components that can only conduct upon being subjected to voltages above a certain threshold This occurs when conductive electrons tunnel probabilistically through a potential barrier in accordance with the laws of quantum mechanics Additional to this general behavior real tunnel junctions display more subtle distinguishing dependencies to a variety of external factors For example the junction conductance may display an implicit dependence on current and voltage Magsimus Deluxe offers a means of specifying if a circuit component is to be treated as a tunnel junction and offers a choice of specific junction models for the component An important class of tunnel junctions have found application in magnetic systems and devices Hirota et al 2002 These so called magnetic tunnel junctions are discussed later on in this chapter System equilibrium calculations Magsimus uses solution techniques that are based on the classical micro magnetic theory Brown 1962 for calculating the equilibrium magnetic state of a system T
127. dow gt Cascade etc play their typical roles in standard Windows applications The functionality of the other menu items are now described File New Problem Readies the program for a new design If an un saved design is currently loaded the user is prompted for verification on whether to discard the loaded design or not Open Initiates the opening of a design file The native Magsimus design files by convention have the default file extension mus Note The file names of the 4 most recently loaded designs are displayed as menu items between the Print and Menu items Save Saves the design to a file If this is the first time the design is being saved the user is prompted for a file name to save the design to If the design has been saved previously or if it were loaded in from a pre existing file then the design is automatically saved without prompting for a file name Save as Saves the design to file by first prompting the user for a file name regardless of whether the design has been saved previously or not Print design Sends the displayed design to an external printer Special Environment settings Displays a dialog for specifying software environment settings for Magsimus See the section Environment Settings below for a description of this dialog System Specifications Displays a dialog for specifying the properties of a system being designed This same dialog is displayed during editing of the system using th
128. down list 3 Lines and Colors tab Select the Element outline option and click the Color button In the Color dialog select a dark color such as dark brown and exit the dialog by pressing the OK button With above specifications a new non magnetic element with the linear dimensions 1000 x 500 x 200 nm will be created Its outline when drawn will be displayed in the color that was specified under the Lines and Colors tab In this tab one may also specify the thickness of the line with which the element s outline is drawn and the color and line thickness for magnetization vector s arrow Press the OK button to quit the Element Specification dialog and complete the creation of the new element Computed time nsk 0 Fig 3 5 System View window displaying first added element The new component is displayed at the system display pane of the System view window Fig 3 5 At the Design Manager box a new highlighted entry New Elementl is now included in the System Structure list Its text is also activated to be edited Change the text to Nonmagnet 1 Note how the listing of this new entry is indented relative to its parent group indicating that it is of a lower level in the system hierarchy Let us now add a second element to the group in a different manner Make sure the lone group is sele
129. e System Design Manager see below Show tip of the day Displays a dialog containing a selection of software usage tips See the section Tip of the day window below for a description of this dialog Batch Job Manager Displays the Batch Job Manager that schedules batch simulations in Magsimus See the section Batch Job Manager later on in this chapter for a discussion of this feature Recording playback Carousel Displays and plays back a collection carousel of various pre recorded simulations This playback process which will be repeated indefinitely can be halted by pressing the Stop button of the Simulation controls in the System view window Refer to the section Recording playback Carousel later on in this chapter to learn more about carousels Reactivate license This re actives the user s license This is useful for recovering from situations in which Magsimus was forced into the demo mode from its normal operation mode after encountering license verification errors See Chapter 2 Getting Started for a discussion of Magsimus Licensing Network Settings Displays a dialog for specifying the network protocol FTP or HTTP that forms the basis of Magsimus internet opera tions Background job monitor Displays a window for monitoring and controling Magsimus background jobs See the section Background jobs in this chapter for a discussion of this window Show system view This displays the System View window This feature
130. e carried out within the External Field Controls frame of the System view window Check the Use field definitions box by clicking on it This prepares the solver to apply to the system during the simulation the field we are about to define If this box were left unchecked the solver would apply to the system the field given by the inputs in the data fields Magnitude Azimuth and Polar Refer to the online help for a detailed description of the external field controls J External field and simulation specifications for system Select field scope System level Group level Static calculation External field specs System parametric simulation specs Field Type Min field Oe 300 Max field De 300 Loop Field leg Polar angle Deg 50 Azimuth angle Deg No of data points 100 Delete Clone Clear All OK Cancel Help Fig 3 12 External field specification dialog Press the Edit button This launches the external field specification dialog box shown in Fig 3 12 External fields can be defined to act on all components of the system as well as on components of selected groups by selecting respectively either of the options System level or Group level inthe Select field scope frame at the top of the dialog box A field definition is made up of a sequence of field legs Refer to the online help for a detailed description of this dialog box Here we define a system level external field consist
131. e input output files used by Magsimus in its operation To report bugs or to make any comments or suggestions contact us by E mail at support MagOasis com or visit the MagOasis web page http www MagOasis com Chapter 2 Getting started System requirements Magsimus Deluxe is a Windows application requiring any of the Microsoft operating systems Windows 95 Windows 98 Windows 2000 Windows XP and Windows NT 4 0 or higher to run It will run within any standard computer hardware configuration that supports these operating systems Naturally performance will improve with increase in system processor speed and main memory RAM capacity Installation You may install Magsimus in your system using an installation file downloaded from MagOasis s web site or a MagOasis supplied CD distribution The installation program for Magsimus Deluxe series is MagSetup exe Magsimus Deluxe software package The fully installed Magsimus Deluxe software package consists of these components The Magsimus design and simulation program A comprehensive and fully illustrated Magsimus user manual e Cellider array patterning and MagJob batch job scheduling and monitoring utilities that are stand alone applications in their own right e Many illustrative design examples and sample recording playback Carousel files stored in the application s Example folder Web installation On your computer desktop double click the Magsimus insta
132. e magnetic design software Copyright 2000 2010 Mag Oasis LLC Software Build MLISD V 60051911 318 Email joti magoasis com Disallowed modules Software licensed to Dr John Oti None Company name MagDasis License type SUPER USER License access type n a License expiration date n a Fig 6 3 Magsimus About box Upper tool bar of main program window Recording and Simulation launch tools The upper tool bar of the main program window provides recording controls used for recording and playback of simulations and the means for initiating and controlling simulations This tool bar is shown in Fig 6 4 Simulation Run in background Bun ause Stop Fig 6 4 Upper tool bar of main program window consisting of recording and simulation launch tools 1 Record button 2 Forward play button 3 Reverse play button 4 Pause button 5 Stop button 6 Replay Go to button 7 Replay mode drop down list About simulation recording Recording of simulations is a powerful and convenient feature offered by Magsimus Recording is useful for later rapid replay and analysis of lengthy simulations that may be very time consuming to run over and over again Recorded data includes all geometric and magnetic states of the design and all defined data outputs of the system components Magsimus also provides a recording playback Carousel described below that provides a means of organizing and playing ba
133. e same solver for both static and quasi static problems Dynamic calculations are fully time dependent The intermediate solution states during dynamic calculations are also time dependent and constitute physical transient states of the system between equilibrium states Both the magnetization and the applied fields are independent of time for static calculations The solution states of the system for quasi static calculations are independent of time For quasi static calculations the change of applied fields in time occurs from the end of one equilibrium calculation to the start of a new one Dynamic Solver In the dynamic solver the magnetization vector of an element changes explicitly with time This is described by either of two time dependent differential equations which expresses the damped precessional motion of the magnetization vector under the influence of an applied field These equations are the Landau Lifschitz LL and the Landau Lifschitz Gilbert LLG equations Mallinson 1987 The LL equation is given by M yt x H 4M x Mx H 2 where ft is time yis the precession factor A is the damping factor and H is the total effective field acting on the magnetization The first right hand term of eq 2 is called the precession term because it represents the tendency of an unconstrained magnetization vector by virtue of its angular momentum to precess indefinitely about the applied field The second right hand term is called
134. ea Defined patterns can be reset quickly by pressing the relevant buttons in this area Layer Pressing this button resets the pattern defined for the displayed layer of the current plane of the array A11 Pressing this button resets all defined patterns of the entire array Data output dialog box l Group Specification 4 Biasing field source Geometry Motion Data Output Electrical Circuit Data type Data category Distance traveled X Generate output Iterations Magnetization External field X Generate graph Energies A Magnetoresistance Generate transient output User defined Options New Delete Clear an Z component of magnetization Mz External field energy density Wext Distance traveled Set output curve lines and colors Units erg cm 3 nm Use custom caption OK Cancel Help Fig 8 11 Specifying output data for a group Data outputs for system components groups elements arrays and probes are defined using similar tab dialogs that are part of their respective properties specification windows This dialog for a group is shown in Fig 8 11 Each data output consists of a set of X and Y values that may be plotted against each other as two dimensional Cartesian graphs during a simulation Any pair of data sets can be specified as output There are no pre defined limits to the number of output data sets that can be defined The following two data outputs are defined for the group in F
135. eck boxes provide visual guides for determining the manner of connections Units tab SL System specifications General Calculation Electrical Circuit Magnetic Electrical CGS C SI Current Voltage Field Oe Milliampere m Millivolt nm M w Microampere u C Microvolt uv Magnetization emu cm 3 E Ampere 4 Volt V Energy density erg cm 3 Time 1 Dynamic time rates r Length Nanosecond ns Linear velocity Nanometer nm Second s m s C mns Micrometer um mmm C Centimeter cm C ns C inns Meter m Nanonewton nN Angular velocity Inch in C Micronewton uN Deg s n Field sweep rate Microinch uin C Newton N C Deg ns gum C Kilonewton kN rpm s ns DK Cancel Help Fig 8 1d Units tab of System specification dialog Units for expressing different physical dimensions in a Magsimus design are specified here Fig 8 1d The units for different types of quantities are organized in different areas of the dialog box Magnetic Length Force etc Two system of magnetic units can be specified the CGI and SI systems In SI units magnetization and field are both expressed in kA m kiloampere per meter in CGS units magnetization is expressed in emu cm electromagnetic units per cubic centimeter while field is expressed
136. ed data sets Y Axis List of descriptions of Y axis data of defined data sets Units This pair of fields under the X Axis and Y Axis lists display the units of the of the currently selected list items under each list Use custom caption Checking this box causes the contents of the input box to the right to be used as the plot caption instead of the default Note A data set is selected by clicking on either its X or Y entry in the X Y Axis lists Y Pressing this button above the X Axis or Y Axis lists defines the selected item in the Data Type list as the X axis Y axis values for the selected data set Note Double clicking the Data Type list defines the clicked item as the Y axis values of the selected data set Data output windows Two types of windows showing graphical plots of data outputs that have been defined for the system components groups elements arrays probes and shields are displayed during a calculation or during the play back of a recorded simulation These are 2 D two dimensional plot windows and parametric plot windows These windows are generated for all specified graphical outputs in the data output dialogs of the system components For the graph of an output definition to be generated first its Generate output and or its Generate transient output selection in the data output dialog must be checked and second its Generate graph selection must be checked as well see the description of the data o
137. eere i derer esi hua eR RR m hne 12 Removable media installation llle 12 Program Group oe betonte a d p b boa debet bet E hee es 12 Magsimus licensing 0 RI IH eh 13 Soft key license usai lllsiesellellsl hh nh na 14 Hard Kay lICense rues up RUP IW OR oe ee eG NE E 14 Chapter3 TutorialS 0 cece eee 15 The Magsimus user interface lille 15 Tutorial 1 Interacting objects llsiiilsieee II 17 ou C 17 System Design Manager l i nen 20 Populating the first group illis III 22 Interacting with the group components 0 0000 ae 28 Defining the remaining groups of the design 0 00 eee eee eee 29 Specifying electrical circuit for first group 6 ee 35 Specifying MONON xi ees xxm peed ae ved Peed aw be re eee P EY ae 38 Specifying an external field 0 0 0 0 cee tees 40 Running the simulation 2 0 0 0000 eee 42 Recording the simulation 0 0 0 0 0 0 cece eee eae 44 SUMMI 25e reb Pete tees Editer tht eed dhe ede Ped a 44 Tutorial 2 Parametric simulation example 020 llle 45 Recording Playback CarouselS 0 llle 49 Magsimus productivity tools 0 2 e Ih 51 Batch Job Manager 00 cece tees 52 Importing Components 0 000 ce eee tees 52 Data recovery mechanisms 0 000 eee ete eee 52 Wide choice of units 2 0 eee 53 Environment settings sissi ssiri turrarani eee ae 53 O
138. elected in the system display pane similar to the one displayed by selecting Set system design attributes menu item For an attribute that is in force a check mark appears next to its corresponding submenu item selecting the item again de selects it the check mark is removed and the attribute previously displayed for the component becomes hidden The items of the submenu depends on the selected component For example Show magnetization vectors item is active for magnetic arrays and single magnetic components but not for probes and shields Remarks For arrays one of the submenus displayed is the Show array outline which offers the options Cells Tight outline Limiting outline and None that determines how the array outline is to be displayed The None option displays the array without any outlines the Cell option displays the cells of the array the Tight outline option hides the cells but displays the limiting outlines of the array that follows any defined patterns the Limiting outline option hides the cells but shows the limiting bounding box containing the array The effects of these choices for a displayed patterned array is illustrated in Fig 7 6 Fig 7 6 Comparison of outline types for a patterned array component a Cells b Tight outline c Limiting outline and d None Lines and Colors Displays the following submenu System Displays a dialog box for specifying colors and sizes of the lines used for drawing magnetic a
139. electrical circuit These are constant and custom current sources A constant current source as the name implies supplies a constant current A custom current source supplies a variable current Two types of variable current profiles are implemented These are the Pulse train and Harmonics currents More complicated current profiles can be generated from an independent sequence of these two types of current profiles Here we discuss Pulse train and Harmonics profiles for dynamic and quasi static calculations that have time as the independent variable Calculation steps replace time in static calculations Pulse train current profile Fig 5 1 01001 pulse train current profile The profile is characterized by maximum current level 5 minimum current level min signal rise time t and delay time fy A pulse train is a sequence of positive and or negative going current pulses of varying durations A pulse train is characterized by a profile pattern a signal rise time t and duration tg a maximum current level Imax and a minimum current level Imin A profile pattern is represented as any combination of zeros 0 and ones 1 A 0 and a 1 has corresponding current levels Ipin and Imax respectively lasting for the duration tg The rise time is the time of transition between current levels A 01001 pulse train with defining parameters is shown in Fig 5 1 Harmonics current profile This is a superposition of in
140. eluxe to represent purely electrical tunneling properties of junctions These properties define the current voltage I V characteristics of the junction as would be measured in electrical circuits that are devoid of magnetoresistive effects In real devices the proba bility of tunneling is modified by the magnetic state of components that are functionally adjacent to the junction as are for instance the case with conventional MTJ sandwich structures In Magsimus Deluxe this process takes place indirectly by means of the changes that occur in the circuit voltage distribution brought about by MR induced changes in the conductance of the device components Once a component has been designated a tunnel junction in Magsimus Deluxe the user is able to select a particular junction model for it see the section Electrical Junction Models below To simulate a pure tunneling junction the component s intrinsic non MTJ conductivity must be set equal to zero A non zero conductivity is treated as a parallel connection to the tunnel conductivity This latter scenario may be useful for the simulation of the so called pin holes that occasionally occur in a real life junction and that can short parts of it electrically The entered conductivity in this case corresponds to the effective conductivity of the pin holes It is usually most convenient to have tunnel junction devices connected to voltage sources that can then be deliberately regulated to co
141. em coordinates Each component of a group also has a coordinate system uvw associated with it The coordinate system of a component is defined relative to the coordinate system of its parent group The relationships between the coordinate systems are illustrated schematically in Fig 4 3 Group U Component Fig 4 3 Coordinate systems of Magsimus a The relationships between system XYZ and group UVW coordinate systems This relationship is illustrated for the first group of the system and the first component of a group The location of the origin and orientation of UVW relative to XYZ is given by the displacement R and angular coordinates 0 polar and azimuth The last couple of coordinates are the angular coordinates of any point on the W axis as measured in the XYZ frame The displacement of a subsequent group of the system can either be measured relative to the system origin or relative to the prior group of the system design hierarchy In the latter case this displacement is measured relative to the last component of the prior group The angular coordinates for all groups are measured relative to the system coordinate frame b The figure on the left illustrates the relationship between the coordinate frame of a group UVW and the local coordinate frame of its component uvw The figure on the right illustrates various ways the displacement of a component s origin such as an element or shield component can be specif
142. entity or an individual and MagOasis LLC MagOasis concerning the software programs Magsimus or Magsimus Custom Applications and the user DOCUMENTATION By using the software you accept the terms of this agreement If you are not willing to do so immediately contact MagOasis for return instructions License Grant MagOasis hereby grants to Licensee a non exclusive license to install and use this MagOasis software SOFTWARE and the DOCUMENTATION accompanying the SOFTWARE DOCUMEN TATION Copyright This SOFTWARE and the DOCUMENTATION are owned by MagOasis and are protected by copyright laws and international treaty provisions No title to intellectual property is being transferred You may not modify reverse engineer de compile or disassemble the SOFTWARE LICENSE IS GRANTED FOR THE LATEST AND SPECIFIC SOFTWARE VERSION AT THE TIME OF PURCHASE IN ORDER TO ACQUIRE NEWER SOFTWARE VERSIONS YOU MAY BE REQUIRED TO REPURCHASE THEM OR BE SUBJECT TO APPLI CABLE UPGRADE FEES AS DETERMINED BY MAGOASIS Installation and Use This license permits Licensee to install and use one copy of the SOFTWARE on a single computer equipped with a software access key in the form of a computer hardware accessory and or license file s provided by MagOasis Licensee is responsible for limiting the number of users to the number licensed which may not be greater than the number of software access keys directly purchased by the Licensee Each copy of the SOFT
143. ents in the system view pane will cause all components of the group to move as one whole Launch all computed curves Displays all calculated curves in a simulation regardless of whether graph plotting was specified or not for some of the outputs when they were specified Calculation control Displays the Calculation control dialog box for controling certain aspects of a simulation This dialog box has the same functionality as the Calculation tab of the System specification dialog box which is described in Chapter 8 About Magsimus Displays the Magsimus About dialog box Cabinet Planar Fig 7 8 Comparison of cabinet and planar projection styles Lower tool bar of main program window System display tool bar lini uu Fig 7 9 Lower tool bar of main program window consisting of system display tools 1 component ock unlock button 2 zoom full button 3 zoom box button 4 zoom last button 5 zoom out button 6 rotate button 7 perspective view button 8 undo button 9 redo button 10 show motion button 11 System view drop down list 12 On display drop down list The lower tool bar of the main program window Fig 7 9 provides system display tools for interactively manipulating the design shown in the system display pane of the System View window 1 Lock controls Pressing this button unlocks or locks design components in place such that geometric dimensions of the system can cannot be modified
144. er 19 R Randomize playback sequence check box in Recording playback Carousel 124 Reactivate license Main program menu item 107 Real part floating sub menu item of 2 D curve window 211 Fourier component in Plot settings dialog box 212 Rec button 44 Record button in main program uppertoolbar 109 record file 166 Recording 230 Recording and Simulation toolbar 108 Recording playback Carousel 122 Redo button 29 in main program lower toolbar 148 Reflection coefficient in Magnetoresistance tab of Array specification dialog 190 reflection coefficient in the formulation of minority spin reflection effective field model 89 reflection polarization factor 89 Relative permeability area in Electromagnetic tab of Array specification dialog 183 184 in Electromagnetic tab of Magnetic Shield specification dialog 200 relative permeability tensor 60 73 Relative to previous component input type in Geometric tab of Magnetic Shield specification dialog 198 input type option in Geometric tab of Array specification dialog 181 input type option in Geometric tab of Element specification dialog 25 input type option in Geometric tab of Probe specification dialog 30 196 Relative to previous group input type option in Geometric tab of Group specification dialog 30 31 33 Relative to the group origin input type in Geometric tab of Magnetic Shield specification dialog 198 input type option in Geometric tab of Array specification dialog
145. eral purpose micromagnetic design software in the business Magsimus is an easy to use personal computer PC based general purpose magnetic design and simulation software It allows one to easily simulate the system response of a magnetic device or circuit under the influence of external magnetic fields currents or local field sources It combines an intuitive graphical user interface GUI with the state of the art in computational micromagnetics and advanced data analysis and visualization Magsimus provides a comprehensive set of tools for the simulation and characterization of magnetic systems It implements many innovative concepts that represent industry firsts enabling magnetic designs to be carried out effectively and accurately A system being designed is displayed in three dimensions and the user can easily interact and modify it using the mouse The user is comfortably isolated from the drudgery of computational details allowing him or her to focus more on the functionality of the design at hand The basic material components are the uniformly magnetized single domain element and magnetic shield objects The size and spatial locations of these components are specified by the user Elements may exist as individual entities or be part of arrays of elements The elements may be magnetic or non magnetic electrically conducting or non conducting shields are always magnetic but may or may not be electri cally conducting An element
146. et 1 Direction of current Current Source wAxs v None Constant Current m fo Custom current profile Een Use as group output Source exit component 2 Edit elect contacts Group circuit diagram Use as group input Connection to other components Source c Destination Component e c fta Nonmagnet 2 Ne E EE x x Direction of current m Axis z Er wm Electrical current waveform specification l Type Pulse train v Signal pattern pia I Leg 1 v Max current level mA of 1 Min current level mA Add No rise time steps Delete No fall time steps Clone No pulse duration steps La Clear All eee Cancel Help c Fig 3 10 Dialogs used in defining electrical circuits and currents To this initial circuit we now connect a current source Make the second component the source component by clicking on it with the right mouse button in the Group circuit diagram box In the Current Source frame select the Custom current profile option Notice that the current source is now included as part of the illustration in the Group circuit diagram box Display the dialog box for specifying the current profile that will be supplied by the current source by pressing the button with caption located to the right of the Custom current profile option This dialog box is shown in Fig 3 10c It allows the creation of a com
147. et output curve lines and colors curve lines and colors Units noe Use custom caption Curve attributes DK Cancel Help Fig 3 6 Data Output tab Above specifications will create a new non magnetic element having linear dimensions 200 x 200 x 700 nm and tilted in space according to the entered angular coordinates in step 1 This element is displaced 500 nm in the W direction from the previously defined element measured in the coordinate frame of the group A graph of the electrical current passing through the element as a function of calculation iterations will be plotted during a simulation Press the OK button to quit the Element Specification dialog and complete the creation of the new element In the System Structure list change the name of the new element to Nonmagnet 2 The system display pane now shows the two components of our first group Fig 3 7 Clicking once at a displayed element with the left mouse button selects it and its parent group Handles in the form of little rectangles that appear at the corners of the element indicate this Select any one of the elements Notice that two sets of handles are displayed Group handles marking the extents of the parent group of the element are displayed in white while handles for the element are displayed in black SSO 8 f electrically energized nonmagnets iet 1 External Field Controls
148. etized element or a surface mesh panel of a shield Oti 1993 The magnetostatic interaction field acting on an element or cell is given by the expression Hy Hj H H 10 where is the self demagnetization field of the element H XDM 12 j is the inter element magnetostatic interaction field and Ns Hs V fo V Gas 13 j Si is the field due to shield sources In eq 11 N is the self demagnetizing tensor of the element It is a diagonal tensor whose diagonal elements are the demagnetization factors of the element In eq 12 D is the inter element magnetostatic interaction tensor of the j th element with respect to the element where Hj is being evaluated the field element and Mj is the magnetization of the j th element Summation is over N magnetic elements in the system with the exclusion of the field element Tensor D can be expressed as follows uu DI Il So t3 uv vv vu D D D iw D ae wu wv ww The tensor D unlike N is a non diagonal tensor Its elements are equal to the components of the volume averaged field per unit magnetization due to the j th element when it is magnetized along its principal coordinate axes For example D is the v component of the volume average field per unit magnetization when the j th element is magnetized along the u axis D is the v component of the volume average field when the element is magnetized along the v axis etc The field term H is found
149. f the system display tool bar is in the unlocked position System display pane action menus Clicking anywhere in the System display pane with the right mouse button displays a menu that allows among other things the opening saving and printing of the current design the selective display of design attributes and the generation of updated reports about the components of the system The following is a full description of these menu items The items Open Save Save as and Print design play the same role as the corresponding items in the main program s File menu see Chapter 6 Magsimus Reference Main program window Show Hide iteration update panel Displays or hides a window that displays certain useful snapshots of system iteration charac teristics These include total computation time time per iteration iteration step sizes free energy density values etc Move group or component manually Displays the Moving Component dialog box that allows the specification of precise amounts for displacing moving groups and components Set system design attributes Displays the following submenu for specifying design display attributes for the design as a whole For an attribute that is in force a check mark appears next to its corresponding submenu item selecting the item again de selects it the check mark is removed and the attribute previously displayed becomes hidden Show magnetization Vectors Tums on off the display of magnetiz
150. field The field is decremented or incremented as the case may be from the maximum field to the minimum field and back to the maximum field in a number of incremental steps specified in the No of data points box The incremental steps are taken between equilibrium states of the system during a simulation The steps are equal for static and quasi static simulations but may vary for a dynamic simulation The duration of the field leg for dynamic and quasi static simulations is specified by Total field duration Rotation external field definition dialog No of data points 100 Field range Oe Start 300 End E 000 Polar angle range Deg Azimuth angle range Deg Start 0 Start 10 End 120 End 360 Do EN Fig 7 15 Rotation external field definition dialog This dialog allows the specification of a Rotation external field leg The dialog is shown as it appears during the specification of a static simulation The labeling changes slightly when dynamic or quasi static simulations are being specified A Rotation field is one whose direction and magnitude are capable of changing simultaneously The initial and final directions of a rotation field are given respectively by the Start and End entries in the Polar angle range and Azimuth angle range areas of the dialog The field s initial and final magnitudes are specified by the Start and End entries of the Field range area The field is swept between its initial and final direc
151. finitions Leg f of m Scale De Simulation Static Ready Computed time rok 0 1247390234311 Fig 6 1 Magsimus start up screen This System View window is described in this chapter Chapter 6 discusses the interface elements of the main program window and Chapter 8 serves as reference for other user interface elements of the software System view window Overview fal System view MR Read Head concept IN Bs RIO MA Read Head concept EB MR Head Pinned layer 1 Free layer A Magnetic bit pattem Domain Domain 2 Domain 3 External Field Controls I Use ld defritons EJL Leg of Field Mode Scale De w 2 08 MET B Azimuth Dea q Polar Deg E l 4 Fig 7 1 System view window 1 integrated Design Manager 2 External field controls 3 System display pane The System view window is where a design is displayed in Magsimus It provides the user with the means to interactively manipulate designs It offers a variety of controls for viewing and modifying the system geometry in different ways and for applying external magnetic fields to the system These features are described in detail in this chapter The System view window is shown in Fig 7 1 It consists of the following areas 1 An integrate
152. frame Parameter category select External Field Loop This indicates that parameters of the previously defined loop field are to be varied during the simulation This option is labeled accordingly to reflect the field type that is selected in the External field specs tab for example the label would read External field Rotation if a defined rotation field was selected Other possible parameter categories are Group and Element GT External field and simulation specifications for system Static calculation External field specs r Parameters Source Azimuthal angle Deg Parameter category Polar angle Deg C Component Number of data points C Group Maximum field Oe Estemal Field Loop Minimum fid 8 Target Polar angle Deq V Generate parametric data Group New Group Component Start value fo End value so No of sweeps fi 0 Ok Cancel Help Fig 3 14 Parametric simulation tab which permit the variation of the design properties of groups and their components see the online help for more details All the parameters that can be varied for the chosen data category are listed in the Source box of the Parameters frame Those of a loop field are currently listed there We will vary the polar angular coordinate of the field from 0 to 90 in 10 steps To accomplish this first select the entry Polar angle Deg in the Source box by clicking on it once Now tran
153. g Magsimus This chapter will mostly discuss the user interface features of the main program window the System view window will be discussed in Chapter 7 while Chapter 8 serves as reference for other user interface elements of the software Jm T Simulation Static Ready Computed time ns 0 247330234311 Fig 6 1 Magsimus start up screen Main program window The main program window consists of several parts that are used for different things These are shown in Fig 6 2 This window consists of two sets of tool bars The upper tool bar the Recording and Simulation tool bar provides the means for controling the recording and playback of simulations and for running simulations the lower tool bar gives the user significant control over the manner of displaying the design in the System View window The program s status bar is located at the bottom of the main program window These parts of the main program window are described further below E MagSimus Deluxe Untitled mus Menus File specs window Help Tool bars ye aa ele p Lo o fe ven Status bar ye Simision Stc Ready Computed tine n 0 Fig 6 2 The parts of the main program window Menus of the main program window Some of the menu items of the main program window File gt Exit File gt Print Win
154. g 185 No of data points box 42 47 in Loop external field definition dialog box 155 in Rotation external field definition dialog box 156 No of sample points box in Pulse external field definition dialog box 157 No of sweeps box in Parametric simulation tab 153 No pulse duration steps box 38 No rise time steps box 37 Nodal analysis 229 None array outline type 142 None option in Electrical Circuit tab of group specification dialog 173 in Electrical Circuit tab of System specification dialog 168 non equilibrium magnetic state 163 Non Magnet 60 Non magnet 183 non magnet 228 Non magnetic element 17 Normal floating sub menu item of 2 D curve window 210 plot type option in Plot settings dialog box 212 Normal magnet 60 182 228 normal magnet 19 normal mode software operation 13 Normal option Relative permeability in Electromagnetic tab of Array specification dialog 184 Normalize M to unity in MR formulas check box in Exchange Coupling tab of Array specification dialog 189 number of coupled components 85 Number of Motion Steps in Motion tab of the Group specification dialog 175 Number of motion steps box 39 O Oe Oesterd 20 On display list in main program lower toolbar 148 Online help 53 Open Main program menu item 106 Open new batch job button in Batch Job Manager 124 Open new Carousel button in Recording playback Carousel 122 Options button in Recording playback Carousel 124 Orientation 185
155. g box which can be used to modify its properties see Chapter 8 Magsimus Reference Component specifications for a description of these dialog boxes Moving and re sizing groups and components Groups and components can be moved and re sized if they are not locked in place A component can be moved by clicking and holding down the left mouse button anywhere within the region it occupies and dragging the mouse A group as a whole can similarly be moved by clicking anywhere within the region bounded by its handles but outside the handles of any of its components A group may also be moved by moving any of its components if the group is first g ued To glue a group right click the mouse on it or any of its components in the system display pane and select Glue group components in the displayed menu Groups and components can be moved by precise amounts by selecting in the Moving Component dialog box that can be launched from the system display pane action menus see below A component can be re sized stretched or shrunk by first clicking and holding down the left mouse button at any of its handles and then dragging the handle The linear dimensions of the component change accordingly to reflect the stretching action A group is similarly re sized When a group is re sized all its components are simultaneously re sized Probe components cannot be re sized Stretching and moving of compo nents can take place only when the Lock Unlock button o
156. ge coupling field amplitude 80 exchange interaction 80 exchange interaction field 75 80 exchange interactions 8 Exchange param A inter element coupling in Exchange Coupling tab of Array specification dialog 187 Exchange parameter A in General Option tab dialog of Environmental Settings dialog 115 exchange parameter A 80 Exclude magnetization dependence inter element coupling in Exchange Coupling tab of Array specification dialog 187 External Field Controls 136 External field controls 150 external field controls 131 External Field Controls frame 40 46 External Field option 47 External field specs tab 41 46 150 in system external field specification dialog 151 External fields 229 externally applied field 75 F Faces to turn off area in Electromagnetic tab of Magnetic Shield specification dialog 200 Fall steps box in Pulse external field definition dialog box 157 Fall time box in Pulse external field definition dialog box 157 Field amplitude box in Pulse external field definition dialog box 157 Field and Waves Electromagnetics 96 field array 7 Field box 46 in Single external field definition dialog box 154 inter element coupling in Exchange Coupling tab of Array specification dialog 187 magnetic anisotropy in Magnetic Anisotropy tab of Array specification dialog 185 Field display pane 136 Field due to currents 78 field editor in system external field specification dialog 151 Field leg list in system externa
157. group at the rate of 18 per step This results in rotation of the group through 360 Display the Group specification dialog box for the bias field source by double clicking its entry in the Design Manager Switch to the Motion tab and define the following two motion legs start each definition by pressing the Add Leg button 1 Number of motion steps 20 In the frame Translation velocity in systen enter Azimuthal 0 Polar 45 Magnitude nm step 40 2 Number of motion steps 20 In the frame Translation velocity in systen enter Azimuthal 0 Polar 90 Magnitude nm step 50 When finished press the OK button to exit the Group specification dialog box The first motion leg defines a translation motion that occurs in 20 steps along the direction given by the angular coordinates measured in the system coordinate frame and will proceed at a rate of 40 nm step The second motion leg occurs in 20 steps at a rate of 50 nm step along the direction specified by the entered angular coordinates We will now preview the motions we specified To preview the motion press the Show Motion button in the main program tool bar button 0 in Fig 3 8 The probe and permanent magnet will move according to the motions defined for them and then return to their starting positions Specifying an external field We now specify an external field that will be applied to the completed design during the simulation This will b
158. he Design Manager press the corresponding action button Element Array Probe Magnetic Shield or Field Array of the component you want to add The component specification dialog is displayed Enter the required data inputs and press the OK button e Right click the mouse in the System Structure list and from the displayed popup menu select the item Add gt component where component is any of the appro priate menu items Element Array Magnetic shield Probe or Field Array The component specification dialog is displayed Enter the required data inputs and press the OK button Each of the new groups that we will create will contain just one component To modify the name of a design component first select it by clicking on it once in the System Structure list then click on it again to edit its text the name entry for a component in is usually ready for editing after the component is first created Group 2 Data inputs in Group specification dialog Geometry tab In the frame Group origin in system coordinate frame nm make sure that the option Relative to previous group is selected in the Input type box then enter X 500 Y 0 Z 500 Exit the group specification dialog by pressing the OK button Change the group name to Probe holder Create a probe component Data inputs in Probe specification dialog Geometry tab Ensure that the option Relative to previous component is selected inthe Input type box then enter
159. he free energy density of the system vanishes every where at equilibrium This condition is also equivalent to the vanishing everywhere of the magnetic torque per unit volume M x H acting on the system where H is the total effective field acting on magnetization M The classical theory assumes a constancy of the magnitude of the magnetization vector at each point of the system i e M const Magsimus assumes that the provisions of the theory resulting from this constraint still hold even when the system contains pseudo soft magnets whose magnetization vectors can change both in magnitude and direction The free energy of the system consists of the following compo nents 1 Energy in an externally applied field often called the Zeeman energy 2 Exchange energy 3 Magnetocrystalline anisotropy or magnetic anisotropy energy 4 Magnetostatic interaction energy Corresponding to each energy term is an effective field term that is proportional to the derivative of the energy density with respect to the magnetization Effective fields are discussed below Dynamic static and quasi static calculation methods In Magsimus a dynamic static or quasi static calculation can be carried out on a completed design The solution of a new equilibrium state from an older one is carried out according to the general iterative algorithm Compute total fields acting at all components Compute response of pseudo soft magnets
160. he locked state for the remainder of this tutorial Other possible actions on components include rotation of components zooming in and out of different regions of the display pane and the display of different side views front back top etc of the design Full descriptions of these actions are available through the online help Clicking anywhere in the system display pane with the right mouse button displays a floating menu that allows among other things the opening saving and printing of the current design the selective display of design features and the generation of updated reports about the compo nents of the system Defining the remaining groups of the design We now add the three remaining groups 2 3 and 4 and their compo nents to the system according to the input specifications given below Use any of the following two methods to add a new group Press the Group button in the Design Manager window the leftmost button on the top action bar The group specification dialog is displayed Enter the required data inputs and press the OK button e Right click the mouse in the in the System Structure list and select the item Add gt Group in the displayed popup menu The group specification dialog is displayed Enter the required data inputs and press the OK button To add a component to a group use any of the following methods in either case first ensure that the appropriate group is selected in System Structure list In t
161. icense See Magsimus licensing software access key 243 Software licenced to Magsimus About dialog box 107 solution steps 20 solver 70 Solver Iteration Control frame in Calculation control tab dialog of Environment Settings dialog 120 Solvers 228 Source box 48 Source Group in Electrical Circuit tab of System specification dialog 168 Source list in Parametric simulation tab 153 Source exit component list in Electrical Circuit tab of group specification dialog 173 in Electrical Circuit tab of System specification dialog 169 Spacing between cells frame 32 in Geometric tab of Array specification dialog 181 Specifying Motion 174 Spectral data type floating menu item of 2 D curve window 211 Spectral Filter plot type option in Plot settings dialog box 212 Spectral filter settings floating menu item of 2 D curve window 211 Spectral filtering as output curve data transformation 82 Spin momemtum transfer SMT 87 spin momentum transfer 189 spin momentum transfer effective field 87 spintronic 90 square potential barrier of Simmons tunnel junction model 95 Start box in parametric output window 214 in Rotation external field definition dialog box 156 Start value box 48 in Parametric simulation tab 153 States sequence display pitch box in Calculation tab dialog of System specification dialog 165 static 69 228 static conditions 8 Static option in Calculation tab dialog of System specification dialog 163 Static
162. ied by the displacement R from the group origin or the displacement R between two elements 1 and 2 For an array component these considerations apply to an imaginary limiting rectangular box bounding the array A probe is characterized by the coordinates of a single point which marks its coordinate origin Review of component properties The basic design components of the system are elements arrays shields and probes Each type of component is characterized by geometric magnetic and electrical properties described below Element Geometric properties An element has a rectangular prism shape An element has a local Cartesian coordinate system uvw associated with it see Fig 4 3 The location of the coordinate origin is defined by speci fying the displacement measured relative to the group coordinate frame of the element from the previous component in the group If the element is the first component of the group then the displacement is measured from the coordinate origin of the group The size of an element is given by its Length measured along the u axis Width measured along v axis and Thickness measure along w axis The angular orientation of element in coordinate frame of parent group is specified by azimuth and polar angular coordinates Electrical properties The element is characterized by an electrical conductivity and electrical current can flow through it in a direction that is parallel to one of its c
163. ig 8 11 1 Z component of Magnetization Mz vs Iterations 2 External field energy density Wext vs Distance traveled For additional information on possible group data outputs see Appendix B Output Data categories Data category List of the predefined categories of output data The data types for an item selected here are listed in the Data type list to the left Data type List of outputs defined for a selected data category Options area Generate output Specifies whether the selected data set is to be generated Generate graph Specifies if a graphical plot is to be generated for the selected data set Generate transient output Specifies if transient non equilibrium data is to be generated for the selected data set during a calculation New Pressing this button defines a new data set Delete Pressing this button deletes the selected data set The user is prompted to confirm the deletion before it takes place Clear A11 Pressing this button deletes all defined data sets The user is prompted to confirm the deletion before it takes place Set output curve lines and colors Pressing this button displays a dialog box for specifyingthe drawing attributes of the plot window for the output curve for the data definition corresponding to the selected entry in the Y Axis list The attributes include the colors and line widths of curves and axes and background colors X Axis List of descriptions of X axis data of defin
164. ign properties ranging from the magnetic units used in simulations to the appearance of certain design attributes of the system Related input fields are organized as tabbed dialogs Figs 8 1a d General tab CM Calculation Electrical Circuit Units Specify element origins in absolute coordinates Max Stored system zoom views Specify group origins in absolute coordinates fi Replay simulation recordings during file open Max Depth of system undos IV Warm user about presence of recorded data before deleting it 20 F Allow auto continue of nomeally terminated simulation m Miscellanoeus Vector Colors and Lines Pinning field Vect inning field Vector E Du C Magnetic anisotropy vector C Electrical Circuit lines zm Thickness Cancel Help Fig 8 1a General tab of System specification dialog Certain general attributes of the system design environment are specified under this tab Fig 8 1a Max Stored System zoom views This specifies the maximum number of prior views of the system that can be retrieved by pressing the Zoom Last button in the System View window Max Depth of system undos This specifies the maximum number of geometric undo operations that is allowed following inter active modifications of the system in the System View window Warn user about presence of recorded data before deleting it Checking this box causes reminders to be posted to the user whene
165. igure an action tool bar that is located above a system structure box Components are added to the design by either clicking the corresponding button on the tool bar or by selecting the appropriate item from a popup menu displayed by right clicking the mouse inside the system structure box These areas are discussed in more detail in the following two sections Action tool bar New components can be added to the design by pressing the buttons of the action tool bar The component properties dialog boxes that are displayed during these actions are described in Chapter 8 Magsimus Reference Components specification 1 Add group Pressing this button displays the group specification dialog box that is used to specify the properties of a new group of the system 2 Add element Pressing this button displays the element specifi cation dialog box that is used to specify the properties of a new element of the group that was selected in the System Structure list 3 Add array Pressing this button displays the array specification dialog box that is used to specify the properties of a new array of the group that was selected in the System Structure list 4 Add magnetic Shield Pressing this button displays the Magnetic shield specification dialog box that is used to specify the properties of a new shield of the group that was selected in the System Structure list 5 Add probe Pressing this button displays the probe specification dialog box tha
166. ilibrium write threshold This value sets the number of equilibrium solution states before a a write to external field Background job monitor 3 Running Job Job name PeadwriteSimul NoSUL muz200 mus Delete iab Job control actions Send terminate signal C Magsimus_Projects MagQasis_ VBP MiscDesign Job folder SOHIUS OSE TEE RHET ROOM Equilibrium write threshold PID 3408 Time started 6 12 42 PM 10 8 2003 1 Apply Queued Jobs Jobs FieldOfT hinfilm mus WritingD ots mus Pip 2 Delete job Time queued 6 1 2 36 PM 10 8 2003 Job folder C Magsimus_Projects MagDasis_VBP Examples Recently completed jobs Jobs Time started 6 1 2 36 PM 10 8 2003 Time completed 6 12 37 PM 10 8 2003 Job folder C Magsimus_Projects MagQasis_VBP MiscDesig Help Fig 6 11 Magsimus Background job monitor Chapter 7 Magsimus Reference System views Introduction The start up screen of Magsimus is shown in Fig 6 1 reproduced below This screen consists of System View Window that is contained in the main program window with caption Magsimus Deluxe Untitled mus In addition to offering a three dimensional rendering of the design as suggested by its name the System View window also provides the means for building the structure of the design and applying magnetic fields to it s External Field Controls T Use field de
167. ill be connected in parallel in the circuit and fed by an external current source Edit the first group i e the entry Group of electrically energized nonmagnets by double clicking its entry in the System Structure list the Group Specifi cation dialog is displayed Select the Electrical Circuit tab Fig 3 10a The elements of the group are represented as rectangles in the Group Circuit diagram box By default the positive direction of current through an element is along the positive u direction of the element The label 1 U for example indicates that the element bearing it is the first element of the group and that the positive current direction is along the positive u axis Any two components that are to be connected to each other are arbitrarily designated as either source or destination components and corresponding areas of the dialog box are used to specify their circuit properties In the Group Circuit diagram box click on the first element using the left mouse button This selects it as the destination component Now click on the second element using the right mouse button to select it as the source component A green box will surround the source component while a yellow box will surround the destination component In the frame Connection to other components select the entry w Axis from the Direction of current drop down list This specifies the positive w direction as the positive current flow direction for the desti nation compone
168. in the selected plane layer layer 1 of plane u v in the figure The arrows drawn inside the rectangles represent the planar projections of the cell magnetization vectors The cell outlines that are removed by patterning are not drawn in the vector map For information on patterning see the section Patterning of arrays above Next to the vector map box at the upper right hand corner is an illus tration of the layout of the array plane relative to its local coordinate frame Below this is a color wheel graded color scale that maps the values of various variables to the colors displayed on the vector map box The color wheel includes annotations of the scale limits and vector component represented by the scale for example in Fig 8 16 this is Mu the u component of magnetization Clicking and holding the left mouse button on a cell in the vector map box displays information about its vector and or scalar component values an annotation area under the vector map box Clicking anywhere on the vector map box with the right mouse button displays a pop up menu that can be used to print the vector map save its data to file select a map type select a base field magnetization exchange anisotropy magnetostatic etc select a data transformation type normal curl or divergence select the mapping variable turn on and off cell outlines edit the color wheel and select the method for scaling the color wheel The scaling method can be absolute
169. ing of only one leg This will be a field excitation that varies in a loop manner First ensure that System level is selected in the Select field scope frame In the External field specs tab add the field leg by pressing the Add button Select Loop in the Field Type drop down list Enter the following inputs Min field Oe 300 Max field Oe 300 Polar angle Deg 50 Azimuth angle Deg 0 No of data points 100 The above specifications prepare us to apply a sequence of fields to the system in 100 equal increments from 300 Oe to 300 Oe and back to 300 Oe along the direction specified by the angular coordinates Press the OK button to exit the external field definition dialog box Running the simulation We are now ready to run a simulation This will be initiated from the main program Recording and Simulation tool bar this was shown in Fig 3 1b and is reproduced in Fig 3 13 Simulation Run in background Bun ause Stop Fig 3 13 Main program Recording and simulation tool bar 1 Record button 2 Forward play button 3 Reverse play button 4 Pause button 5 Stop button 6 Replay Go to button 7 Replay mode drop down list Make sure that the Run in background box is unchecked in the Simulation frame in the main program tool bar then press the Run button that is located in the Simulation Controls frame This begins the simulation After a few moments windows that will contain the gr
170. ing time steps that are appropriate for arriving at a solution Consequently the generation of non equilibrium out put data that are separated by equal time intervals is not guaranteed by this method Additionally the computation if allowed to continue unhindered will terminate only when the user specified convergence tolerance see below is satisfied For the user defined method the user specifies a time step to be taken per solution iteration Internally the solver strives to advance the solution by using this time step The solver may not always succeed in this if unacceptable computational errors may accrue as a result However the user defined method will generate non equilibrium outputs that are separated by the specified time step An unhindered simulation in the case of a user specified method will con clude whenever the convergence criterion is satisfied Time step per iteration Specifies the time step to be taken between non equilibrium calculation states This applies only to user defined dynamic calculations Apply this total time bound Checking this box causes the total computed phys ical time not to exceed the value entered in the box to the right of this check box This applies only to dynamic and quasi static calculations Calculate to full relaxation option Checking this box indi cates that the solution is to proceed to full relaxation Maximum number of iterations Applies only to Static calcula tions Specifies the
171. inuing the simulation from the recovered state of the design Enable check pointing Checking this box enables background check pointing processes to take place during a simulation This box is checked by default Note The state of the Enable check pointing box applies only to the currently loaded design and does not automatically extend to all subsequent designs Check point transient states Checking this box allows transient solution states to be saved together with equilibrium states during the check pointing of a simulation Equilibrium states only are check pointed by default Check pt iteration threshold This specifies the periodic number of solution iteration states that is to be skipped between check pointing of a simulation Electrical Circuit tab E System specifications X Calculation Electrical Circuit Source Group 1 MRAM Device group Current Source C None Constant Current m o C Custom current profile per Source exit component n 1 B Destination Group 2 Word line cse e CT oeste d OK Eancel Help Fig 8 1c Electrical Circuit tab of System specification dialog The system electrical circuit is defined here Fig 8 1c The circuit is defined by specifying the electrical connections between the groups making up the system as well as system level electrical current sources and their connections The system electrical circuit is a higher level
172. ion dialog 182 Material button in Material library dialog 220 Materials Library 182 Materials library 220 227 Max current level box 37 Max Depth of system undos box in General tab dialog of System specification dialog 162 Max field box 41 47 in Loop external field definition dialog box 155 max Harmonic input in Spectral filter settings dialog box 211 Max M rotation angle box in Calculation tab dialog of System specification dialog 166 Max no of allowed workstations Magsimus About dialog box 108 Max stored system views 147 Max Stored System zoom views box in General tab dialog of System specification dialog 162 Maximum 165 maximum current level Imax 67 Maximum depth of system undos 148 Maximum no of electrical self field source segments per side 78 Maximum number of iterations input in Calculation control tab dialog of Environment Settings dialog 120 Maximum number of iterations box in Calculation tab dialog of System specification dialog 165 meshes 73 Meter m 116 Microampere uA 117 Microinch uin 116 micromagnetic 68 228 micromagnetics 7 Micrometer um 116 Micronewton uN 117 Microsoft 11 Milliampere mA 117 Min current level box 37 Min field box 41 47 in Loop external field definition dialog box 155 min Harmonic input in Spectral filter settings dialog box 211 Minimize curve windows at start of simulation option in General Option tab dialog of Environme
173. is particularly useful for re displaying the System View window after it had been closed unintentionally Download software updates This initiates the search and download of remote software upgrades that are available on ET servers Help About Magsimus Displays the About dialog box of Magsimus Fig 6 3 The About dialog box displays the current Magsimus version number copyright information and the following license information Software licensed to This is the name of licensee Company name Company or organization of licensee License type The type of license that was extended SUPER USER HARD KEY etc License access type The means by which license resources are accessed Possible access types are via the global internet or vendor supplied hard key accessory License expiration date The expiration date of the current license Max no of allowed workstations Applies only to licenses that are accessible through the global internet This is the maximum number of separate computers in which Magsimus can be run in simultaneously under the currently assigned license In each computer an unlimited number of instances of Magsimus can be run simultaneously Disallowed modules area This lists the Magsimus modules that cannot be used under the current license These may be Arrays Electrical Circuits Magnetic Shields or Magsimus User Extensions About Magsimus Magsimus Deluxe Version 6 0 General purpos
174. it is displayed is shown by right clicking the mouse on the System display pane Descriptions of this menu and various system interaction mouse actions and their effects are covered in this section gt v Fig 7 5 System display pane of the System View window Mouse actions at the System display pane Selecting components Clicking once at a displayed component selects it When a component is selected handles in the form of little rectangles appear at the corners of the region occupied by the component Group handles are displayed in white while handles for the components making up a group are displayed in black Selecting a component also selects its group The handles of a selected group and one of its components the upper one are shown in Fig 7 5 The components of a selected group can each be selected in turn by repeatedly pressing the space bar This selects the elements sequentially by their positions in the group If the whole system is on display that is the system entry is the one selected in the On display list of the System display tool bar then pressing the space bar further after the last component of the group has been selected transfers the selection to the first component of the group at the next group position If a component alone is on display then pressing the space bar does not change its selection on the display pane Double clicking a component on a pane displays its properties display dialo
175. its Licensee to install and use one copy of the SOFWARE on a single computer equipped with a software access key in the form of a computer hardware accessory and or license file s provided by MagOasis Licensee is responsible for limiting the number of users to the number licensed which may not be greater than the number of software access keys directly purchased by the Licensee Each copy of the SOFWARE may be used on a backup computer or replacement computer when a software access key is used Licensee must not service or otherwise tamper with the normal opera tions of the software access key Licensee may use the SOFWARE only for its internal operations by its own employees or those of its subsidiaries or parent company Licensee may not make the SOFWARE available for use by third parties Licensee must discontinue using the SOFWARE in its normal mode of operation after the date of expiration of the license as indicated in the About dialog box of the Help menu of the main program window unless autho rized otherwise explicitly by written permission of MagOasis Termination MagOasis may terminate this license by written notice to Licensee if Licensee 1 breaches any material term of this agreement 2 fails to pay the amount charged for this license within 45 days after delivery or 3 ceases conducting business in the normal course Licensee may terminate this agreement at any time by written notice to MagOasis Licensee shall not be en
176. ity o The magnetic force output for a probe 1s the total force summed for all the objects within which the probe lies Thermal Modeling The magnetic characteristics of real objects depend on temperature In general magnetocrystalline and shape induced anisotropy fields tend to decrease at elevated temperatures Energetically this can be explained in terms of the energy well that separates hard and easy anisotropy direc tions The thermal energy absorbed by the body as its temperature is increased statistically perturbs the energy resulting in a decrease of effective depth of this energy well Two types of thermal models are implemented in the software a Classic MagOasis legacy model and a Stochastic model A description of these models follows Classic Thermal Model The classic model is a simple thermal model that neglects the dynamics of thermal variations It is assumed that the establishment of thermal equilibrium in the device occurs instantaneously and that the temperature is uniform throughout a magnetic unit a single component or an array cell of the sample The following first order approximation is used to model thermal effects in the Magsimus H H 0T 0 lt H lt H 35 where H is the magnitude of a uniaxial pinned magnetocrystalline or shape anisotropy field H is the anisotropy field at absolute zero of temperature equal to approximately 273 C 050 is a phenomeno logical temperature coefficient of
177. ization vector of an element Make this a tunnel junction Checking this box indicates that the component would be treated as a tunnel junction component in calcu lating its electrical behavior within the system electrical circuit Clicking the button Edit junction to the right displays a dialog box for specifying the junction properties Conductivity Specifies the electrical conductivity of the array Input current axis The input direction of current through the component is selected from this list Output current axis The output direction of current through the component is selected from this list Edit electrical contacts Displays a dialog box for editing the input and output electrical contacts of the component refer to the section Specifying electrical contacts for arrays above Relative permeability area Applicable only to a pseudo soft magnet Value Specifies relative permeability of an array cell to be used in calcula tions if the Normal option is selected T uu T vvandT_ww Specifies relative permeability diagonal tensor values of array cells if the Anisotropic option is selected Normal Selecting this option indicates that the relative permeability speci fied in the Value field is to be in calculations Positive Infinity Selecting this option indicates that the each array cell has a permeability of plus infinity Negative Infinity Selecting this option indicates that each array cell has a permeability
178. l Y data set as a function of the X data set The trapezoidal rule is used to compute this integral The upper and lower integral limits are at each data point are the current and prior x data val ues Thus the last Y data point represents the total algebraic area enclosed by the base curve Derivative This is the derivative of the normal Y data set as a function of the X data set The secant rule is used to compute this derivative X Fourier spectrum or Y Fourier spectrum Thisis the Fourier decomposition of the normal X or Y data set The original data set is re sam pled into a new set numbering an appropriate power of 2 before the transfor mation is carried out The Fourier transform in general results in a functional set of complex numbers versus integral harmonics whose characteristics can be individually plotted based on the sub menu choice made under the Spectral data type submenu see below Low pass X Low pass YorLow pass X Y Selecting any of these menu items applies the appropriate low pass filtering to the various x and Y data sets Low pass filtering is obtained from the inverse transformation of Fourier data in which the spectral components larger in absolute values than a prescribed threshold value are suppressed The threshold spectral value is spec ified in the dialog box displayed by selecting the Spectral filter set tings menu item see below High pass X High pass YorHigh pass X Y Selecting any of these
179. l field specification dialog 151 field legs 137 Field Mode box in External Field Controls 138 field probe 17 Field range area in Rotation external field definition dialog box 156 field sequence 137 Field sweep rate list in Start up Units tab dialog of Environmental Settings dialog 117 Field Type list 41 47 Field type list in system external field specification dialog 151 File type filter list in Importing components window 225 Files list in Importing components window 225 Flannery B P 97 force 230 Force list in Start up Units tab dialog of Environmental Settings dialog 117 foreground jobs 126 Forward play button 44 Forward play button in main program upper toolbar 109 free energy density 68 free energy minimum 163 Freeze surface charges during calculations check box in Calculation Controls tab of Magnetic Shield specification dialog box 202 front view of design 148 FTP protocol 107 fundamental period 68 G general potential barrier of Simmons tunnel junction model 95 General Provisions 245 247 Generate output check box 208 in dialog for specifying output data for a group 207 Generate parametric data check box 47 208 in Parametric simulation tab 152 Generate transient output check box 207 208 Geometric properties of elements 59 63 Geometry tab 23 25 30 33 Giant magnetoresistance GMR 228 ouput of 84 Giant Magnetoresistance GMR coupling area in Magnetoresistan
180. l field specification dialog 151 inter element coupling in Exchange Coupling tab of Array specification dialog 188 Delete component button in Magnetoresistance tab of Array specification dialog 190 Delete item button in Batch Job Manager 125 in Recording playback Carousel 124 Delete Leg button in Motion tab of the Group specification dialog 175 Delete menu in integrated Design Manager 135 demagnetization factors 76 demonstration demo mode software operation 12 Demonstration Evaluation license agreement 245 Derivative as output curve data transformation 82 floating sub menu item of 2 D curve window 210 plot type option in Plot settings dialog box 212 Design component Array 61 Element 59 Field array 64 Probe 63 Design examples 15 Design Manager 131 Design primitives 228 Design projection attributes in General Option tab dialog of Environmental Settings dialog 115 Destination component list in Electrical Circuit tab of group specification dialog 174 Destination Group list in Electrical Circuit tab of System specification dialog 169 Deviation box Easy axis orientation in Magnetic Anisotropy tab of Array specification dialog 185 Magnetic vector distribution in Electromagnetic tab of Array specification dialog 183 dipolar 75 Direction of current in component box in Electromagnetic tab of Array specification dialog 184 in Electromagnetic tab of Magnetic Shield specification dialog 200 Direction of current list 35 in Electrical Ci
181. ld Patterning of arrays atterming array 1 1 New Element Layer 1 of U V plane a Time ns 0 2311 40 1813 71 Displayed component New problem s e AA ALA ALY EALA ZLz7 Cpe FS eee AA Pe i D Sa M aa mit Vina Ww OW WoW rm E gt b Fig 8 10 Patterning of an array a Patterning dialog box b The patterned array of a on display array in the System display pane Array components in Magsimus can be patterned into a variety of shapes Patterning of an array involves the selective eliding of its cells This enables the carving out of complex shapes from array components This capability greatly enhances the design versatility of Magsimus The array patterning dialog window is shown in Fig 8 10a This dialog is displayed by any of the following actions 1 Right click the mouse on an array icon in the System structure box of the Design Manager refer to Chapter 7 for a description and select the item Pattern array from the displayed floating menu 2 Right click the mouse on the array component directly in the System display pane and select the item Pattern array from the displayed floating menu The vector map occupies much of the left hand side of the window The small rectangles within this area represent the outline of the array cells in the selected plane layer layer 1 of plane u v in the figure The arrows drawn inside the rectangles represent
182. lete Pressing this button deletes a selected item of materials library from the database The user is prompted to confirm the deletion before it takes place Summary Pressing this button displays a window containing a summary of the properties for the selected item of the Materials library I Material electromagnetic properties library Current definition Generic Add to database Database entries Permalloy U film specimen Select Cobalt Edit Delete ec OK Cancel Fig 8 18 Materials importation dialog Specifying electrical current signals Custom and constant current sources can be included in group and system electrical circuits see the topic Electrical Circuit tab in the sections System specification window and Group specification dialog box above A constant current source as the name implies supplies a constant current A custom current source supplies a variable current The signal from a custom source is a sequence of basic signal profiles called egs Two types of signal legs are implemented These are Pulse trains and Harmonics Each one of these basic profiles is characterized by a variety of properties see below Complicated signal profiles can be synthesized by combining the basic profiles The dialog box for specifying the signal profile of a current source is shown in Fig 8 19 The framed data specification area on the left side of the dialog box the
183. line help support Help buttons are located throughout the dialog boxes and other interface elements of the software All online help are context sensitive which means that help information pertaining only to the currently active dialog box or window is displayed when its help button is pressed Use the help buttons to learn about the meaning of the controls and data fields you are working with Chapter 4 Design components and coordinate frames In this chapter we describe the various design objects and the coordinate systems used by Magsimus System component hierarchy Magsimus uses a top down three level hierarchy to represent a magnetic design At the top of this hierarchy is the system object or simply system which represents the problem to simulate Only one system at a time can exist in the program A system can consist of one or more groups at the second level of the design hierarchy A group in turn may contain basic components corresponding to the lowest level of the design hierarchy Systems devoid of groups and groups devoid of basic compo nents are said to be empty The basic design components are elements arrays probes magnetic shields or simply shields and field arrays Elements and shields have rectangular prism shapes An array is a collection of elements located in a three dimensional rectangular grid The elements making up an array are referred to as cells A field array is a special array of points for visuali
184. llation file downloaded from the MagOasis web site to start the installation Follow the ensuing setup instructions to complete the installation Removable media installation Connect the MagOasis provided installation removable media CD jump drive etc your computer in the normal way and follow these steps 1 Click on the Windows Start menu and select Run The Run dialog appears ii Click the Browse button and navigate to the file named MagSetup exe located on the appropriate drive assigned to your removeable media iii Click the Open button iv In the Run dialog box click the OK button Follow the setup instruc tions to complete the installation Program Group Upon installing Magsimus a new program group called Magsimus Deluxe containing several icons will be created in your system Click on the Magsimus icon in this group to run the program The program will usually then operate in demonstration demo mode You need to install a license file supplied by MagOasis in order to run the program in its normal mode and take full advantage of its simulation capabilities see Magsimus licensing below for more information Click on the User Manual icon to display the software User Manual The User Manual is a Portable Document Format PDF file You must have a PDF reader such as the Adobe Acrobat Reader installed in your computer to read this document The utilities Cellider and MagJob are started by clicking their i
185. m display pane action menu 141 Show Magnetization Vectors System display pane action menu 141 Show magnetization vectors check box in Importing components window 226 Show Motion button 40 Show motion button in main program lower toolbar 148 Show output contact tab box in Electrical contact properties dialog box 177 Show system view Main program menu item 107 Show tip of the day Main program menu item 106 System display pane action menu 145 Show tip of the day at start up option in General Option tab dialog of Environmental Settings dialog 114 SI 116 SI units 65 Signal pattern box 37 Simmons model 95 Simulation area in main program upper toolbar 110 Simulation Controls frame 42 Simulation state in status bar panel of main program window 111 Simulation type in status bar panel of main program window 111 sine wave components 67 single external field 154 single domain element s 7 single layer thin film structure 88 Size of array cell frame 31 in Geometric tab of Array specification dialog 181 in Geometric tab of Magnetic Shield specification dialog 199 Skip backward button in Batch Job Manager 125 Skip backwards button in Recording playback Carousel 123 Skip forward button in Batch Job Manager 125 in Recording playback Carousel 123 Slonczewski J C 87 97 SMT field per current in Magnetoresistance tab of Array specification dialog 190 SMT see spin momentum transfer 189 soft key license 13 Soft key l
186. mA s Iterations iof x Fig 8 12 A 2 D plot window To zoom into a particular area of the plotted graph click and hold down the left mouse button over one corner of the intended zoom region Without releasing the mouse button drag the mouse to the intended corner opposite the first a zoom box is swept out while dragging the mouse upon releasing the mouse button the region contained in the zoom box is displayed to fill the whole plot window Double clicking the mouse anywhere in the plot area or re sizing the window restores the full view of the plotted graph and redraws it Clicking the right mouse button anywhere in the plot area displays a floating menu that can be used to store the plotted data to file send its graph to a printer or modify the drawing attributes of the plot window colors and line widths of curves and axes and background colors etc Several curve attributes may be modified simultaneously by selecting the menu item Plot attributes gt Settings The displayed dialog box for accomplishing this is described in the section Plot Settings Dialog Box below The Plot type menu item displays the following sub menu items a curve of the selected item is displayed and the curve window caption is appropriately re named to reflect the choice made Normal default This is the base output that is specified by the user for a component for example in its properties editor Integral This is the integral of the norma
187. magnetization dependence M M j in 20 while specifying an exchange coupling for a component This is accomplished by checking the box Exclude magneti zation dependence in the dialog box for specifying the properties of the component see Chapter 6 Specifying design components Note The exchange field expression 20 is a classical derivation that imposes certain constraints on the validity of the formula The classical theory in particular assumes small angular variations between neighboring magnetization vectors Magsimus applies the formula as is without consider ation to the constraints Output data Data outputs to be generated or that are to serve as data sets of graphs to be plotted during a simulation are described here These outputs are generated for groups and basic components elements arrays probes and shields The discussion that follows includes information on how the outputs are interpreted for the different design components Data outputs are organized in categories in the data output specification dialogs of the software A complete listing of the data outputs is given in Appendix B Output data categories The user curve data defined and plotted in a simulation can be further transformed into other related outputs These transformations are plotted on the curve window of the underlying data by the selection of appro priate items in the floating menu that is displayed upon right clicking the mouse button anywhe
188. maximum number of iterations allowed between equilib rium states Convergence tolerance Specifies the value of the terminating criterion for the calculation which must be satisfied for a fully relaxed solution to be deemed achieved The convergence tolerance is the maximum angle between the magnetization and total effective field vectors at any component of the sys tem Show equilibrium magnetic states Checking this box causes equilibrium magnetization states to be displayed during a simulation Show transient iteration states Checking this box causes non equilibrium magnetization states to be displayed during a simulation States sequence display pitch Specifies the number of frames iterations to skip between successive displays of magnetic states of the design during a simulation Graph re plot pitch Specifies the number of points to skip between re plots of graphical output curves during a simulation Track M rotation angle Applies only to dynamic calculations Checking this box imposes a restriction on how far magnetization vectors can rotate between non equilibrium states during a simulation Max M rotation angle This is enabled by checking the Track M rotation angle box This specifies an upper bound to the angular rotation of magnetization vector between non equilibrium iterations during a simulation Restore initial system geometry at end of simulation Checking this box will cause the initial geometric state of the
189. me taken equal to the numerical integration time step y is the precession factor of 3 V is the volume of the computational cell and o is a user supplied pre factor Tunnel Junction Models This section contains summary descriptions of electrical tunnel junction models currently implemented in Magsimus Deluxe These descriptions offer minimal outlines of the models as an aid to the understanding of the relevant dialog box inputs of the program The reader should refer to the cited references for a more complete narrative of the models The models predict the current voltage J V characteristics of the junction as a function of barrier height a voltage and barrier width a length Usually the current depends on these properties in a fairly complex way Simmons model Two flavors of the Simmons model are implemented Hirota et al 2002 Formulations for i a general potential barrier and ii a square potential barrier The model predicts a current density due to an applied voltage of V that is given by 1 1 A 2 2 J eee U 4 Vie Pa V J Bw 38 for the general barrier and by Nie Nine y A u p e u pus 2 39 for the square barrier where 4 is a unit dependent pre factor U is the mean barrier height Ug is the constant barrier height of the square potential and p is a model dependent correction factor The formulas are applicable to applied voltages that are less in absolute value
190. me in place of Rise steps The field magnitude remains at the amplitude value over a number of steps given by the Duration steps entry displayed as simply Duration for dynamic calculations The field amplitude is then returned to the base value in a number of steps given by Fall steps Fall time for dynamic and quasi static calculations The entry No of sample points applies only to dynamic and quasi static simulations This corresponds to sample points of the field profile between equilibrium states Report windows Reports summarizing the properties of a system its groups and the components of groups can be generated from the System display pane of the System view window A report window is displayed by selecting the Reports item of the floating menu displayed by clicking anywhere in the System display pane using the right mouse button This displays a floating sub menu with items System report Group report Component report from which can be selected the desired report The report window of an element is shown in Fig 7 17 Clicking anywhere in the window with the right mouse button displays a floating menu that can be used to print the report or save it to file The following information are contained in the reports System A description of the system A description of the group composition of the system e An indication of whether a system electrical circuit is defined or not A description of the system calculation me
191. ment and any number of current sources may be included in the circuit A group electrical circuit may be defined by connecting together the components of the group Group electrical circuits may be combined together to form a system electrical circuit Electrical circuits of virtually any complexity may be designed using dialogs for specifying system and group properties Probes and field arrays cannot be used as circuit components Each circuit component has an electrical conductivity input output 1 0 electrical contacts and a designated current flow direction that is parallel to one of the local coordinate axes and which defines the ends at which the i o contacts are located The corresponding positive coordinate direction serves as the positive direction of current flow between a pair of contacts Current distribution inside components Currents are assumed to flow uniformly in single element and shield components Current may not flow uniformly in an array due to geometric and material inhomogenieties among it cells The distribution of current in an array is calculated by solving an electrostatic field problem in which the boundary conditions are given by the voltage levels obtained from the system circuit analysis The currents produce magnetic fields that combine with the fields from other sources to influence the magnetic behavior of the system Electrical current sources Two types of current sources can be specified in a Magsimus
192. ments are not listed as they cannot be coupled to Delete component Pressing this button deletes the currently selected GMR coupling definition The user is prompted to confirm the deletion before it takes place Group Displays the description of the parent group of the component cur rently selected in the Components list Components Drop down list of components that are currently GMR cou pled to Each component description is preceded by the notation n m where n is the parent group designation of the component and m is the position of the component in the group Note The following inputs can vary separately for each GMR coupling definition Pre Factor Catch all pre factor that typically reflects the GMR ratio commonly referred to as AR R of the array being GMR coupled to Refer to the User Manual for more information on GMR ratio and this factor Enable SMT minority carrier reflection Checking this box enables the inclusion in calculations of SMT related minority spins reflection effects This reflection occurs at the coupled component Reflection coefficient This value expresses the reflective quality of a coupled component This input is relevant when the box Enable SMT minority carrier reflection is checked Lines and Colors tab i Array Specification 1 1 Flux concentrator Electromagnetic Geometry Magnetic Anisotropy Exchange Coupling Magnetoresistance Lines and Colors Calculation Control User defined Para
193. ms Data Output Stimuli sources C Aray outline aH Magnetization vector arrow Current density vector arrow a Iesu x Vector arrow tip angle 15 Cancel Fig 8 6f Lines and Colors tab of Array specification dialog box The appearance of the outline of an array and the arrows of the magneti zation vectors of its cells when displayed are modified here by speci fying line colors and widths Fig 8 6f Array outline Current density vector arrow and Magnetic vector arrow options Selecting either option allows its corresponding attributes to be modified Color Pressing this button displays a dialog box for editing the line color The currently selected color is displayed at the swatch to the left of this button Line thickness The line thickness is specified here either by typing in a value in this space or by selecting a value from the drop down list A sample of the current line is displayed at the swatch next to the left of the input field Vector tip angle applies to magnetization and current density vectors Determines the shape of the arrow tip of the vector arrow repre sentation Calculation Control tab iG Array Specification 1 1 Flux concentrator Electromagnetic Magnetic Anisotropy Exchange Coupling Magnetoresistance Lines and Colors ol User defined Params Data Output Dynamic equation properties Field vector conditionings Ignore U component of field Damping
194. n Group Specification 2 Probe holder Motion Data Output Electrical Circuit Motion Leg No 1 Yv of 2 Return group to this leg s initial position after it terminates ES CERSIES Number of Motion Steps 20 ETE m Translation velocity in system frame Azimuthal Deg o Polar Deg 0 Azimuthal Polar 18 Magnitude nm steps 0 Angular velocities of rotation Deg Step OK Cancel Help Fig 3 11 Motion tab of the Group specification dialog Display the Group specification dialog box for the probe holder by double clicking its entry in the Design Manager and select the Motion tab Fig 3 11 This tab is used to specify motion for the group Group motion is defined as an arbitrary sequence of motion legs Each leg describes a translation and or rotation of the group By defining a variety of motion legs in this way the group can be made to undergo complex motions during a simulation Legs are numbered starting from 1 onwards The resulting motion follows sequentially from the defined legs One motion leg will be required to define the rotation of the probe holder Press the Add Leg button to create this leg Enter the following inputs Number of motion steps 20 In the frame Angular velocities of rotation Deg Step enter Azimuthal 0 Polar 18 Click OK to exit the dialog box The entered specifications define the rotation of the group by 20 incre ments of polar angular coordinate of the
195. n dialog 151 Add element button in integrated Design Manager 133 Add field array button in integrated Design Manager 133 Add group button in integrated Design Manager 133 Add item button in Batch Job Manager 125 in Recording playback Carousel 124 Add Leg button in Motion tab of the Group specification dialog 175 Add Leg button motion 39 Add magnetic shield button in integrated Design Manager 133 Add menu in integrated Design Manager 134 Add probe button in integrated Design Manager 133 Add to database button in Material library dialog 220 Adobe Acrobat Reader 13 algorithm 69 70 All reset button in array patterning dialog box 205 Allow MR to modify array conductivity option in Magnetoresistance tab of Array specification dialog 189 Allow MR to modify element conductivity option in Magnetoresistance tab of Array specification dialog 189 Along u box 32 array matrix dimension in Geometric tab of Array specification dialog 181 coupling field within array in Exchange Coupling tab of Array specification dialog 187 spacing length in Geometric tab of Array specification dialog 181 spacing length in Geometric tab of Magnetic Shield specification dialog 199 Along v box 32 array matrix dimension in Geometric tab of Array specification dialog 181 coupling field within array in Exchange Coupling tab of Array specification dialog 187 spacing length in Geometric tab of Array specification dialog 181 spacing length in Geomet
196. n gt The parts component designation and output description are composed similarly as for the 2 D plot windows described above The middle part of the caption Y vs X indicates that the output description corresponds to the output that was specified for the component The Z variable s are the defined parameters for the simulation Thus X vs Y are computed for varying Z The parameters are listed in the Parameter zZ box in Fig 8 15 The entry for each parameter in the list is prefixed according to the following notation e n Parameter of the n th group of the system e n m Parameter of the m th component of the n th group of the system fn Parameter of the n th external field leg applied to the system The range of variation of a parameter that is selected in this box is given by the Start and End fields to the left the Current box displays the current simulation value of the selected parameter The Parametric plot box displays a perspective view of the family of generated parametric plots This display appears as a surface plot Clicking with the right mouse button in this box displays a floating menu with the following items Save As Saves the surface plot data to file Print Prints the surface plot Show Cut Displays a cutting plane on the surface plot a 2 D plot of the cut points is displayed in the Cut trace box to the left of the parametric plot box A cutting plane is displayed in Fig 8 15
197. n in Plot settings dialog box 212 X Fourier spectrum floating sub menu item of 2 D curve window 210 X Axis list in dialog for specifying output data for a group 207 Xmax input box in Plot settings dialog box 212 Xmin input box in Plot settings dialog box 212 X Y 48 X Y option cutting plane in parametric output window 214 X Z 48 X Z option cutting plane in parametric output window 214 Y Y input in Geometry tab of Group specification dialog 171 Y Axis list 31 32 46 Y box 30 31 33 Y Fourier Spectrum plot type option in Plot settings dialog box 212 Y Fourier spectrum floating sub menu item of 2 D curve window 210 Y Axis button in dialog for specifying output data for a group 207 Y Axis list 26 Ymax input box in Plot settings dialog box 212 Ymin input box in Plot settings dialog box 212 Y Z 48 Y Z option cutting plane in parametric output window 214 Z Z input in Geometry tab of Group specification dialog 171 Z box 30 31 33 Zeeman 69 Zhu J G 80 97 Zoom box button in main program lower toolbar 147 Zoom full button in main program lower toolbar 147 Zoom Last button in main program lower toolbar 147 Zoom near component in integrated Design Manager 136 Zoom near group in integrated Design Manager 136 Zoom out button in main program lower toolbar 147
198. nate system of design components Component origin in group coordinate frame Specifies the location of the origin U V W of the component in its group The selection in the Input type box Relative to previous component Relative to the group origin determines how the origin input is to be interpreted The default input type can be specified in the in environment dialog box reached by selecting the main program menu item Special gt Environment settings Angular orientation coordinates within group Specifies the angular orientation coordinates Azimuthal Polar of the array measured relative to the coordinate frame of the parent group of the array Linear dimensions along coordinate axes Specifies the linear dimensions Length Lu Width Lv Thickness Lw of the shield along its local coordinate axes Surface mesh divisions Specifies the inputs that define the rectangular surface mesh of the bounding faces of the shield on which the magnetic surface charge distributions are induced Along u Along v Along w Each dimension gives the number of mesh panels along the corresponding coordinate axis Pressing the Set auto mesh button sets the mesh dimensions to default values that are proportional to the lengths of the sides Electromagnetic tab f Magnetic Shield Specification 1 1 Field shield cover User defined Params Data Output Calculation Control Geometry Electromagnetic Lines and Colors AA ASME Poo
199. nd arrays in the system An element cannot be exchange coupled to a shield or a probe The implementation of exchange coupling in the software is a general ization from classical theories An exchange coupling field characterizes the exchange interaction Exchange interaction promotes the parallel or anti parallel orientation of the magnetization of the coupled elements Magnetoresistance The conductivity and resistivity of an element may change as its magneti zation changes in response to applied fields This phenomenon is called magnetoresistance The element can exhibit two kinds of magnetoresis tance of different physical origins Anisotropic magnetoresistance AMR and giant magnetoresistance GMR Magnetoresistance is characterized by an MR ratio which is the relative change of the conduc tivity of the element from its intrinsic value AMR depends on the local magnetic state of the element while GMR depends on the local state as well as the magnetic states of certain neighboring components Speci fying those neighbors is part of specifying the GMR characteristics for the element Dynamic properties An element is characterized by gyro magnetic and damping constants that determine its response during dynamic calculations Array An array is a collection of geometrically identical elements located in a three dimensional regular rectangular grid The elements of an array are called cells Geometric properties A local coordina
200. nd colors Pressing the Next Scan button at any time during a simulation termi nates the current scan and starts a new one The simulation is terminated or paused by pressing the Cancel simulation button or the Pause button 2 D Vector Map window f 1 1 Array Vector Map u Be il BH Be S m 4 gt Close Help Cell 5 5 Vector Vu Vv 277 6829 110 2228 Scalar 110 2228 e He Fig 8 16 A 2 D Vector Map window The 2 D Vector Map window Fig 8 16 displays a two dimensional vector map of the magnetization state of an array component as well as certain of its internal effective field components This same window is used to view the current density field But we will discuss it here in the context of magnetization and effective field components The original form of each of these fields is considered base fields whose curl and divergence transformations may also be generated and displayed The curl and divergence of a vector field F are given by the spatial deriva tives VxF and VeF This window is displayed by selecting the item Vector map from the pop up menu that is displayed in the System Display pane after clicking on a selected array component with the right mouse button the current density map is displayed by selecting Current density map item from the pop up menu The vector map occupies the left hand side of the window The small rectangles within this area represent the outline of the array cells
201. ndow during calculations Use the following links to obtain a description of the respective field types and their input dialogs Field type This is a drop down list of field types Single Loop Rotation Pulse The selection in this list is the operational field type for the field leg currently being edited See the section External field type inputs below for a discussion of the configuration of data input areas for the various field types Field leg This is a drop down list of the leg positions of the field sequence Selecting an item in this list displays its definition in the field editor area Add Pressing this button adds a new leg to the field sequence Delete Pressing this button deletes the currently selected field leg The user is prompted to confirm the deletion Clone Pressing this button identically replicates the selected field leg and appends the new entry to the Field leg list Clear all Pressing this button removes all field leg definitions The user is prompted to confirm the deletion Parametric Simulation specs tab EJ External field and simulation specifications for system Static calculation External field specs Parametric simulation specs r Parameters Iv Generate parametric data Source Length Lu nm Parameter category Width Lv nm Component Thickness Lw nm C Group Azimuthal orientation Deg C Extemal Field Loop Polar orientation Deg Target Group Thicknes
202. nes of new designs are specified here Modification of the displayed attributes apply to the currently selected option Color Pressing this button displays a dialog box for editing the line color The currently selected color is displayed at the swatch to the left of this button Line thickness The line thickness is specified here either by typing in a value in this space or by selecting a value from the drop down list A sample of the defined line is displayed at the swatch next to the left of the input field Calculation control tab E Environment settings e So General Options Start up Units Color attributes Calculation control Solver Iteration Control Calculation Method Use Default method C Use user defined method C Static C Quasi static Dynamic Equation LandauLifschiz Maximum number of iterations gt 0 200 Convergence Tolerance Deg 0 5 System thermal model Classic kd New component magnetostatic truncation tolerance 0 0 1 Fig 6 7d Calculation control attributes tab of the Environment Settings dialog Certain default calculation attributes for new designs are defined in this tab Calculation method frame The calculation method Static Quasi static or Dynamic to be used during simulations is selected here For a static calculation both the magnetization and magnetic field components are independent of time Consequently with this method both dat
203. netostatic truncation region surrounding the component For each component the target Magsimus maintains a computation list of objects that fall within its magnetostatic truncation region The larger the magnetization of an object the source and the closer it is to the target component the more likely it is to fall within the target s truncation region An object is included in this list if it satisfies the following condition L 2 0252 2 s 15 where M and M are the magnetization magnitudes for the source and target L is the length of the smallest side of the source R is the is the magnetostatic truncation tolerance The latter can be specified in the distance between the centers of the source and target and System specification or the Calculation control dialog boxes of the software see the relevant sections in Chapter 6 Specifving design components The criterion is applied uniformly to all components of the system The full magnetostatic interaction between components occur when e 0 Field due to currents To calculate the field acting on an element due to electrical currents flowing in the system the source current carrying components are subdivided into segments Fig 5 4a The largest possible number of segments on a side is given by the entry Maximum no of electrical self field source segments per side inthe Calculation control tab of the source component s properties specification dialog
204. new replacement key we provide at no additional cost to you A key swap requires that the defective key be first returned to MagOasis following which MagOasis then sends you the replacement key MagOasis maintains a database of key information of its deployed hard keys This information may be used to authenticate the identity of keys received by us during the swapping process Only properly authenticated keys may be swapped Under no circumstance shall MagOasis be responsible for any loss in productivity that may be incurred by you the customer during the hard key swap process However when feasible MagOasis may at its discretion but not by obligation arrange for a temporary bridge soft key for you during the swap period You are strongly encouraged to carefully safeguard your keys against loss Under no circumstance will MagOasis replace a lost key A new key can be provided only as part of a new software product purchase Index Symbols 7 crsl files 237 dat files 238 mbat files 238 mus files 237 Numerics 2 D Plot window 208 2 D plot windows 238 2 D plots 227 2 D Vector Map window 215 2 D vector plot window 208 3 D surface plots 227 A A m Ampere per meter 20 About Magsimus Main program menu item 107 System display pane action menu 146 action toolbar in integrated Design Manager 133 Add array button in integrated Design Manager 133 Add button 37 41 47 in system external field specificatio
205. ng this button deletes a component from the interaction list The user is prompted to confirm the deletion before proceeding Calculation Control tab iG Magnetic Shield Specification 3 2 Field shield cover Electromagnetic User defined Params Data Output Magnetostatic truncation tolerance 0 1 Include self fields in the calculation of charge map V Use mean field approximation for interactions with shields Reset surface charges at start of calculations Freeze surface charges during calculations OK Cancel Help Fig 8 9c Calculation Controls tab of Magnetic Shield specification dialog The Calculation control tab Fig 8 9c allows the user some control on the manner of computing the behavior of the shield component Magnetostatic truncation tolerance This specifies a criterion that defines the extent of magnetostatic interactions with other components in the system see Chapter 5 for more details Include self fields in the calculation of charge map Checking of this box indicates that the self field of the shield component due to its own surface charges is to be included in the total surface field terms for computing induced surface charges Use mean field approximation for interaction with shields Checking this box causes the interaction field acting on this shield component due to its other shields in the system to be computed using a mean field approximation Refer to Chapter 5 for a dis
206. ng this button displays a dialog that allows the specifica tion of a new component to exchange couple to Probes are not listed as they cannot be exchange coupled to Delete Pressing this button deletes the currently selected exchange defini tion The user is prompted to confirm the deletion before it takes place Magnetoresistance tab E pi Element Specification 1 1 Flux concentrator p Lines and Colors Calculation Control Y User defined Params Data Output Stimuli sources Electromagnetic Di Geometry Magnetic Anisotropy Exchange Coupling Magnetoresistance T V Use intrinsic conductivity as lower bound value in GMA model Allow MR effect to modify element conductivity Anisotropic Magnetoresistive AMR Ratio 0 Giant magnetoresistance GMR coupling V Enable spin momentum transfer SMT effects with coupled components SMT field per current De m 100 Couple new component Delete coupling Group Component 2 1 Shunt cap Y Sensor i GMR pre factor 2 8 V Enable SMT minority carrier reflection Reflection coefficient 0 lt Val lt 1 0 8 OK Cancel Help Fig 8 6e Magnetoresistance tab of Array specification dialog box Magnetoresistive MR characteristics of the array are defined here Fig 8 6e Magnetoresistance is the dependence of the resistivity or conduc tivity of a component on its own magnetic state and those of its neighbors Tw
207. ng this license agreement or if you desire to contact MagOasis for any reason please e mail MagOasis at info magoasis com Purchase license agreement for long duration licenses The following applies to you if you have purchased a copy of Magsimus Magsimus Custom Application or other MagOasis software NOT through our Pay per use Online Store This license agreement represents the entire agreement between you Licensee either an entity or an individual and MagOasis LLC MagOasis concerning the software programs Magsimus and the user documentation By using the software you accept the terms of this agreement If you are not willing to do so immediately contact MagOasis for return instructions License Grant MagOasis hereby grants to Licensee a non exclusive license to install and use this MagOasis software SOFTWARE and the documentation accompanying the SOFTWARE DOCUMENTATION LICENSE IS GRANTED FOR THE LATEST AND SPECIFIC SOFTWARE VERSION AT THE TIME OF PURCHASE IN ORDER TO ACQUIRE NEWER SOFTWARE VERSIONS YOU MAY BE REQUIRED TO REPURCHASE THEM OR BE SUBJECT TO APPLI CABLE UPGRADE FEES AS DETERMINED BY MAGOASIS Copyright This SOFTWARE and the DOCUMENTATION are owned by MagOasis and are protected by copyright laws and international treaty provisions No title to intellectual property is being transferred You may not modify reverse engineer decompile or disassemble the SOFTWARE Installation and Use This license perm
208. ng time steps that are appropriate for arriving at a solution Consequently the generation of non equilibrium output data that are separated by equal time intervals is not guaranteed by this method Addi tionally the computation if allowed to continue unhindered will terminate only when the user specified convergence tolerance is satisfied In the user defined method the user specifies a time step to be taken per solution iteration Inter nally the solver strives to advance the solution by using this time step The solver may not always succeed in this if unacceptable computational errors may accrue as a result However the user defined method will generate non equilibrium outputs that are separated by the specified time step Always calculate to full relaxation Checking this box indi cates that the solution to a calculation is to proceed to full relaxation Maximum number of iterations This specifies the maximum num ber of iterations allowed between equilibrium states Convergence tolerance This specifies the value of the terminating criterion for the calculation which must be satisfied for a fully relaxed solution to be deemed achieved The convergence tolerance is the maximum allowed angle between the local magnetization and field vectors at equilibrium System thermal model The default thermal model Classic or Stochastic for components of the system is specified in this drop down list New component magnetostatic truncation t
209. nisotropy and electrical circuit illustrators of the displayed system This dialog box is described in the section Editing Lines and Colors below Component active only if a component is selected in the system display pane Displays a dialog box for specifying colors and sizes of the lines used for drawing the selected component s outline and in the case of array and sin gle components its magnetization vector s This dialog box is described in the section Editing Lines and Colors below Show array M color wheel applies only to arrays Causes a color wheel to be displayed in the system view window above the system display pane The color wheel represents the manner in which the coloring of magnetization vectors is associated to a variations of compo nents of the vector field see also the discussion under menu item M vector field color guide Fig 7 7 shows the color wheel representing the M component of the displayed patterned array When this menu item is in force the applicable color wheel is displayed whenever an array is selected in the system display pane Double clicking a color wheel displays a dialog box for editing it This dialog box is described in the section Editing Color Wheels below Fig 7 7 Illustration of color wheel for a patterned array on display in the system display pane Edit M color wheel applies only to arrays Displays a dialog box
210. nline help 00000 Rr 53 Chapter 4 Design components and coordinate frames 55 System component hierarchy 0 000 eee eae 55 Coordinate system sernam see us er gh ede ee p ede seeder RR E E 57 Review of component properties 000 eee 59 Elements cs vad aan ett peated E Nave du e E ded que rei ide s aot rele Beto n 59 Magnetic shield alsace de m Roe Raga ede RR ERR MR e 63 cM LC ne 63 Field Artay cc suse ivee EX Abba aaa ae Yu ted aa d pbi d 64 Chapter5 Mathematical Theory 000 ee eee eee eees 65 Electrical GIFCUlts 2 eere pay tei ace SE oe dra eq Se acetone EPR ae 65 OVOIVIOW cole ep eIS bide pb ida te tana awa e eae dda peda 65 Current distribution inside components 000000 eee eens 66 Electrical current sources 1 eee 66 Pulse train current profile liliis 66 Harmonics current profile llle 67 Tunnel Jurictions ollas e lbelxd3 rad 4g Ehud X444 4 bed 68 System equilibrium calculations llle 68 Dynamic static and quasi static calculation methods 69 Pseudo soft magnet response 0 cee es 72 Magnetic shield model 0 cette eae 73 Effective fields 0 000 eee 74 Magnetostatic interaction field 0 0 llle 75 Magnetostatic truncation region 0 ee eee 77 Field due to currents 2 0 2 0 eee eae 78 Magnetic
211. nnections Probe components are ignored in electrical circuits Any two components that are to be connected to each other are arbitrarily classified as either source or destination components and corresponding areas of the window are used to specify their circuit properties Electrical circuits of the groups making up the system may be combined together to form a system electrical circuit Group circuit diagram Displays a schematic of the system electrical circuit The diagram is continually updated as the circuit is modified Each component is displayed as a rectangular box in this area l Group Specification 1 Group of electrically energized nonmagnets Geometry Data Output Electrical Circuit Source Component 1 Nonmagnet 1 Direction of current Current Source uwAxis v None Constant Current m Custom current profile al Use as group input Use as group output Edit elect contacts Connection to other components Destination Component Lr 2 Nonmagnet 2 Direction of current w Axis fx SA p Dest Cancel Fig 8 2b Electrical Circuit tab of group specification dialog Clicking once on a displayed component in this area using the left mouse button selects it as the source component and surrounds it with a green box Clicking with the right mouse button selects the component as a destination component and surrounds it with a yellow box Source Component area
212. ns before pulling them into the larger one Data recovery mechanisms Accidental data loss in abnormally terminated calculations is a reality of life in all software and Magsimus is of course no exception Simulations may terminate abnormally for a variety of reasons such as sudden system crashes or the premature expiration of a license in the middle of a simulation Magsimus through its Check Pointing feature provides safeguards against accidental data loss by enabling the recovery of a significant portion of the final state of the terminated simulation and making it possible to resume computation from the recovered state Wide choice of units Magsimus offers a rich choice of practical units for specifying the physical quantities that characterizes a design These units enable the different ways of expressing electromagnetic time length and rate quantities used in the designs All users can easily avail themselves of the wide choice of units that best meets their varied design needs Simply specify the units that meet your fancy and leave it to Magsimus to figure out the details Environment settings Magsimus provides users with the means to tailor the software environment they work in to conform to their specific tastes and needs These can range from system color attributes and computation units at program start up to default simulation control switches for newly created designs Online help Magsimus provides a comprehensive on
213. nt Notice that the label for the first component in the Group circuit diagram box has now changed to express this fact Inside the Connection to other components frame to the right is a set of check boxes for accomplishing the connection of source and destination components The straight lines connecting the check boxes provide visual guides for determining the manner of the connections between the components Check two of the boxes as shown in Fig 3 10b to accomplish the parallel connection of the components The connec tions will show up as part of the circuit diagram in the Group circuit diagram box Try out other possible connections by clicking among the check boxes to see their effects and to get a feel of how they work and then revert back to the setting indicated in Fig 3 10b iG Group Specification 1 Group of electrically energized nonmagnets m Source Component 1 Nonmagnet 1 Direction of current Current Source Group circuit diagram uAsis z None Constant Current m o F Use as group input Custom current profile iml Use as group output Source exit component Edit elect contacts Connection to other components Destination Component E 1 Nonmagnet 1 Y Direction of current LEO he mH Dest E Group Specification 1 Group of electrically energized nonmagnets Data Output Electrical Circuit m Source Component m Nonmagn
214. nt back left right top and bottom are displayed by toggling with the button to the left of the system view area Show magnetization vectors Checking this box causes the drawing of magnetization vectors of the system displayed in the System views area Show Electrical circuits Checking this box causes the drawing of defined electrical circuits of the system displayed in the System views area Show Mag Anisotropy axes Checking this box causes the drawing of defined magnetic anisotropy vectors of the system displayed in the System views area Show Coordinate axes Checking this box causes the drawing of the coordinate frames in the system displayed in the System views area Import The importation of a design is accomplished by pressing this button The component importation window is closed after pressing this button Cancel Closes the component importation window without any action being taken Appendix A Magsimus features at a glance Flexible and easy to use graphical user interface Powerful data display features vector maps shield charge maps 2 D plots and 3 D surface plots Transformation of element into array Patterning of array into custom shapes Three dimensional natural form rendering of designs Comprehensive three dimensional CAD environment Full interactivity with design Stretch move and rotate designs even during a simulation Environment settings Set your Magsimus start up and simul
215. ntal Settings dialog 114 minimum current level Imin 67 Minor tic marks frame in Plot settings dialog box 212 Minority spin reflection effect of spin momentum transfer SMT phenomenon 89 Miscellaneous vector Colors and Lines area in General tab dialog of System specification dialog 163 Model box Dynamic equation in Calculation Control tab of Array specification dialog 193 Motion 229 Motion Leg No list in Motion tab of the Group specification dialog 175 motion legs 39 Motion tab 39 Mouse pointer coordinates in status bar panel of main program window 111 Move group or component manually System display pane action menu 141 multilayer sandwich thin film structure 88 MUS DeluxeSetup2x exe Magsimus installation file 11 MUSCli cli license file 237 MUSLic cli Magsimus license file 13 N Nanometer nm 116 Nanonewton nN 117 Nanosecond ns 117 Negative Infinity option Relative permeability in Electromagnetic tab of Array specification dialog 184 Network Settings Main program menu item 107 New button 26 in dialog for specifying output data for a group 207 New component magnetostatic truncation tolerance in Calculation control tab dialog of Environment Settings dialog 120 New Problem Main program menu item 105 Newton N 117 Next Scan button in parametric output window 215 nm nanometers 20 No warranty 246 No fall time steps box 38 No list in Magnetic Anisotropy tab of Array specification dialo
216. ntion For example the label u v means that u is the horizontal axis pointing to the right and that v is the vertical axis pointing downwards Layer The cell layer parallel to the selected plane is specified here either by entering a value in the box or by moving the slider to a new position Magnetic shield charge maps 6 172 Shield surface charge map Face UV1 normal top Bk Face eunt Cum COW Owe C ywi C Vw 15 89868 9 812647 Fig 8 17 Magnetic shield charge map window The charge map window Fig 8 17 displays a two dimensional scalar map of the induced magnetic charge distribution formed on the faces of a magnetic shield due to its interaction with other magnetic components of the system This window is displayed by selecting the item Shield charge map from the pop up menu that is displayed in the System Display pane after clicking on a selected magnetic shield component with the right mouse button The charge map occupies the left hand side of the window and is color coded The plotted map corresponds to the selected option in the Face frame UV1 in Fig 8 17 The rectangular grid on the map of Fig 8 17 represents the grid that is defined for the shield face in determining its charge distribution this grid can be turned on and off Each rectangular cell of the grid is called a panel to avoid confusion in the use of the term cell for array components To the right of the cha
217. ntly being edited Pulse train A Pulse train is a sequence of positive and or negative going pulses of varying durations The profile editor of Fig 8 19 contains the dialog for specifying a pulse train shown is the editor displayed for a static calcu lation The pulse train is characterized by a Signal pattern No rise time steps rise time for dynamic and quasi static calcu lations No of pulse duration steps Duration for dynamic and quasi static calculations Max current level and Min current level See Chapter 5 Mathematical Theory for a discussion of pulse train Harmonics A Harmonics signal leg is defined as the sum of several sinusoidal components A sinusoidal term is called a harmonic and is charac terized by an amplitude and phase The dialog that is used for defining the Harmonics current leg is shown in Fig 8 20 See Chapter 5 Mathematical Theory for a discussion of Harmonics fS Electrical current waveform specification Fundamental characteristics l3 SR No Pts per period Harmonics E No of periods 4 st l Leg 1 of 1 Harmonic definitions Add Definition aM of 2 Delete Harmonic f Add Clone Harmonic Amplitude mA f Clear Delete All Phase Deqg 30 Harmonic OK Cancel Help Fig 8 20 Harmonics signal leg definition dialog Importing components Magsimus provides the capability for importing external designs into a currently loaded one The design of a complex s
218. ntly selected option Clicking the button labeled launches a standard dialog for edit ing the color The currently selected color is displayed at the swatch above this button Line thickness frame The line thickness width for drawing the axes and the curve in the plot window is defined here my making appropriate selec tions in the drop down lists Axes and Curve Data markers frame Curves can be plotted with or without markers Markers are used indicate the actual location of data points on the plot Check ing the box Show data markers causes markers to be drawn Checking the box Use solid symbols causes solid or filled markers to be drawn un checking this box causes only marker outlines to be drawn markers are drawn using the same line thickness as curve lines The size and type of a marker Circle or Box are defined using the drop down boxes Marker sizeandMarker symbol The Color button is used to specify a color for the marker Clicking this button launches a standard dialog for editing the color of the marker The currently selected color is displayed at the swatch to the left of this button Parametric output window fea 1 1 vs X Magnetization along external field Mh emu cc Vs System external field a EIC E3 Fig 8 15 A parametric output window A parametric plot window is shown in Fig 8 15 The general format for the caption is component designation gt Y vs X output descriptio
219. ntrol junction behavior This can easily be accomplished in Magsimus Deluxe by connecting the device in parallel to the component of a separate circuit that is connected to a current source This is illustrated in Fig 5 5 Voltage source Current source Junction device Fig 5 5 Illustration of the parallel connection of a tunnel junction device to a voltage source in Magsimus Deluxe The voltage source is simulated by a simple circuit of a resistor and current source connected in series Magnetic force The magnetic force F acting on an element or the cell of an array is the force due to the interaction between the external magnetic field acting on the element and the free magnetic poles induced on its bounding surfaces This force is given by the following summation over the six bounding faces of the element 6 F Y o 4 H 33 i 1 where o M n is magnetic pole density per unit area of the i th face M is magnetization of the element n is unit outward normal of the i th face A is its area and Hj is the average external field acting on the face The total force acting on an array is the sum of the forces acting on its constituent cells The force that acts on a magnetic shield component is due to the inter action between the induced surface magnetic charge distributions of the shield and applied fields It is given by the expression F c HdS 34 S where H is the field acting on the point with charge dens
220. o kinds of magnetoresistive behavior of different physical origins are modeled 1 Anisotropic Magnetoresistance AMR and 2 Giant Magnetoresistance GMR AMR depends on the local magnetic state of the component while GMR depends on the local state as well as the magnetic states of certain neighboring components Specifying those neighbors is part of specifying the GMR characteristics The physical details of the interaction of a component with its neighbor leading to GMR is summarized here by referring to GMR coupling between components Refer to Chapter 5 Mathematical Theory for more infor mation on magnetoresistance Note AMR and GMR effects can occur simultaneously in an element The definition of magnetore sistance is irrelevant in the calculations of non magnetic elements Normalize M to unity in MR formulas option Checking this box specifies that unit magnetization vectors are to be used in magnetore sistance formulas see the sections Giant magnetoresistance and Aniso tropic magnetoresistance in Chapter 5 for a discussion of MR models used by Magsimus If this box 1s not checked normalized magnetization vectors not necessarily of unit magnitude are used instead in the formulas Use intrinsic conductivity as lower bound value in GMR model Checking this box applies the assumption that the intrinsic conductivity supplied by the user specified under the Electromagnetic tab is to be used as a lower bound conductivity
221. obe specification dialog The appearance of the outline of a probe is modified here by specifying the color and width of the line used in drawing the probe Color Pressing this button displays a dialog for editing the line color The currently selected color is displayed at the swatch to the left of this button Line thickness The line thickness for drawing the probe is specified here either by typing in a value in this space or by selecting a value from the drop down list A sample of the currently specified line is displayed at the swatch to the left of the input field Magnetic Shield specification dialog box Geometry tab amp Magnetic Shield Specification 1 1 Field shield cover User defined Params Data Output Calculation Control Geometry Electromagnetic Lines and Colors Component origin in group coordinate frame nm Angular orientation coordinates within group Dea Input type Relative to the previous component x Azimuthal 0 u 0 ao Polar 0 w 500 Linear dimensions along coordinate axes nm Surface mesh dimensions Length Lu 1500 sue Hm 110 Width Lv 1000 Gc 2 Thickness Lw 50 Ae Set auto mesh OK Cancel Fig 8 9a Geometry tab of Magnetic shield specification dialog The coordinate origin the linear dimensions and the angular orientations within the parent group of the shield is defined here Fig 8 9a See Chapter 4 for additional information on the coordi
222. of a group uvw The location and orientation in space of group coordinate frames are specified relative to the system coordinate frame and the origin and orientation of the coordinate frames of basic components are specified relative to the coordinate frames of their parent groups Coordinate systems are discussed in Chapter 4 Calculation methods The simulation that will be performed on the system will be a static one The software will invoke a static solver to carry out the calculations The static method is the default calculation method The other calculation methods that are available in the software are dynamic and quasi static methods The system state including magnetization and applied magnetic fields are independent of time for static calculations Therefore for this method the duration and the rate of change of physical quantities are expressed in the input dialog boxes of the software in terms of solution steps for example linear velocity is expressed in dimensions of Distance step On the other hand the states of a modeled system using the dynamic and quasi static methods are time dependent For these methods duration and rates of change are expressed in terms of time Magnetization states are not time dependent for quasi static methods A separate solver the dynamic solver is invoked for dynamic calcula tions Quasi static calculations share the same solver as static calcula tions During quasi static calculations
223. of a group is calculated by the expression VM Me 21 L where V and M are the volume and magnetization of the i th component of the group and N is the number of components of the group Magnetic induction B is related to the magnetization and field H as follows B u H M 22 where p is the permeability of free space Magnetic induction output is not computed for groups Magnetization and magnetic induction output for a probe is obtained from the vector sum of the total magnetization and magnetic induction vectors for all the components intersecting the probe Energy density Energy density of a component due to an effective field term H is given by H M 23 The energy density of a group is found as the average of the energy density of its components Energy density output is not generated for probes Electrical current and voltage For elements and arrays these are the electrical voltage across a component and the electrical current that flows through them The current is assumed to flow uniformly in the component regardless of its microstructure For a probe the calculated current is equal to the algebraic sum of the currents flowing in the components that intersect the probe The voltage output for a probe is the algebraic sum of the voltage drops in the components that intersect the probe Current and voltage outputs are not generated for groups Note The patterning of an array is assumed to have no effect
224. of the group The magnetic fields produced by the fictitious sources are not accounted for in calculating the magnetization processes Self GMR response of an array In the above formulation of GMR a component can be GMR coupled to any other component in the system including itself In the case of an array coupled to itself equation 25 above applies to each array cell Thus each cell is treated as being GMR coupled to its nearest neighbor cells and the dot product contribution of a neighbor is assumed propor tional to the magnitude of current flowing through it This makes the self GMR response to be dependent on the current distribution in the array Note An array that is GMR coupled to itself is the easiest way of modeling GMR response of granular single layer films Spin momemtum transfer SMT phenomenom An intriguing phenomenom in certain GMR multilayer film samples is the interaction between spin polarized electrical current and magneti zation This manifests itself in the form of a spin momentum transfer between the sense current and magnetization in GMR multilayers see for example Berger 1996 and Slonczewski 1996 Thus in addition to its usual role of sensing resistance change the sense current can alter directly the magnetization state of the sample through the mechanism of momentum transfer This fact holds the promise of ushering in as yet un tapped novel technological applications It has been shown Slonczewski 19
225. of the projection style The cabinet and cavalier styles results in the design in three dimensional perspective the planar style results in a two dimensional perspective of the design Cabinet and planar perspective views of the same design are compared in Fig 7 8 Reports Displays a report window for the selected window see the section Reports below for adescription of this window Show tip of the day Displays a dialog box containing a selection of software usage tips See the section Tip of the day window in chapter 6 for a description of this dialog Vector plot applies only to arrays Displays a window for viewing two dimensional magnetization vector maps of the selected array component This window is described under the topic 2 D Vector Map window in Chapter 8 Current density map applies only to arrays Displays a window for viewing two dimensional current density vector maps of the selected array component This window is described under the topic 2 D Vector Map window in Chapter 8 Shield charge map applies only to magnetic shields Displays a window for viewing the surface charge distributions formed on the faces of the selected shield component This window is described under the topic Magnetic shield charge maps in Chapter 8 Glue Un Glue group components Clicking this glues or un glues a group that is selected in the system display pane When a group is glued then moving any of its constituent compon
226. oint P using eq 17 in text Magnetic anisotropy fields The total magnetic anisotropy field acting on a component element or array cell is the sum of the anisotropy fields from the collection of anisotropies defined for the component Each anisotropy may be uniaxial or pinning The pinning anisotropy is a unidirectional anisotropy charac terized by a constant field H acting in a fixed direction The uniaxial anisotropy is bi directional Thus the magnetic anisotropy field is given by the expression ING H gt HH 18 j 1 where N is the number of defined anisotropies The uniaxial magnetic anisotropy field acting on a component is given to first order by Zhu and Bertram 1989 H H m k k 19 where H is the magnitude of the anisotropy field and k is a unit vector in the direction of the component s easy axis The field H is related to the magnetization M of the component and its magnetic anisotropy constant K by H 2K M Exchange interaction field The exchange interaction promotes the parallel or anti parallel orien tation of the magnetization of coupled components depending on whether the specified coupling field amplitude is positive or negative The exchange field H acting on the i th component due to a j th component that is exchange coupled to it is given by H M Myj m m 20 ex z where H is the exchange coupling field amplitude M is the magneti zation of the j th component
227. olerance Defines the default criterion that defines the extent of magnetostatic interactions between components in the system see Chapter 5 of the user manual for more details Tip of the day window Productivity enhancing tips on the use of Magsimus can be displayed in a variety of ways By selecting Show tip of day i in the main program s Special menu or ii from the pop up menu displayed by right clicking with the mouse on the display pane of the System View window Tip information is displayed in the Tip of the day window Fig 6 8 Magsimus maintains a data base of tip information Pressing the Next Tip button causes information in the next tip position to be displayed Pressing the Previous Tip button causes information in the previous tip position to be displayed The user can cause the tip of the day window to be always displayed during Magsimus start up by checking the Show tip of the day at start up box under the General Options tab of Environment Settings dialog box see section above Checking the box Do not show tip at start up disables this feature El Tip of the Day Did you know that In Magsimus you can always learn about a dialog box or window you are currently using simply press the Help button for the window to get all the help information you need Such is the power of context sensitive online help l4 I Do not show tip at start up n Pi 1 Close Fig 6 8 Tip of the day
228. om caption in dialog for specifying output data for a group 207 Use default method option in Calculation tab dialog of System specification dialog 165 se field definitions box 40 46 se field definitions check box in External Field Controls 137 Use interface coupling option inter element coupling in Exchange Coupling tab of Array specification dialog 187 Gs ce Use intrinsic conductivity as lower bound value in GMR modelbox in Magnetoresistance tab of Array specification dialog 189 Use macrospin model in Calculation Control tab of Array specification dialog 193 Use mean field approximation for interaction with shields check box in Calculation Controls tab of Magnetic Shield specification dialog box 201 Use SMT classic model in Magnetoresistance tab of Array specification dialog 189 Use solid symbols check box in Plot settings dialog box 213 Use user defined method option in Calculation tab dialog of System specification dialog 165 Use volume average magnetostatic fields in Calculation Control tab of Array specification dialog 193 V V origin in Geometric tab of Array specification dialog 181 Origin in Geometric tab of Magnetic Shield specification dialog 198 Origin in Geometric tab of Probe specification dialog 196 V box 25 30 Value box Relative permeability in Electromagnetic tab of Array specification dialog 183 Vector distribution coordinates frame in Electromagnetic tab of Array specification dialog
229. omponent of anisotropy field HaniV Magnetic anisotropy w component of anisotropy field HaniW Anisotropy field magnitude Hani Anisotropy energy density Wani u component of exchange field HexcU v component of exchange field HexcV Exchange w component of exchange field HexcW Exchange field magnitude Hexc Exchange energy density Wexc u component magnetostatic interaction field HmstU v component magnetostatic interaction field HmstV w component magnetostatic interaction field HmstW Magnetostic interaction field magnitude Hmst Magnetostatic interaction energy density Wmst u component self demagnetizing field HdmU Magnetostatic v component self demagnetizing field HdmV w component self demagnetizing field HdmW self demagnetization field magnitude Hdm self demagnetization energy density Wdm u component field from shield sources HShldU v component field from shield sources HShldV w component field from shield sources HShldW u component total field HtotU v component total field HtotV w component total field HtotW Total field magnitude Htot Total fields Table 1 2 Data output Categories for elements These apply to arrays for which outputs averaged over the array are generated Data Category Data type Anisotropic magnetoresistance AMR Conductivity change due to AMR Giant magnetoresistance GMR Conductivity change due to GMR Magnetoresistance Current Voltage
230. oms can be carried out Double clicking the vector map reverts it back to the un zoomed state Materials library Magsimus supports the creation and management of a materials library This is a database containing pre defined material types that can be imported as part of the properties of an element or array component Each database entry is characterized by a magnetization a conductivity magnetoresistive properties and magnetic anisotropies The dialog box for importing a material type is shown in Fig 8 18 This dialog box is displayed by pressing the Material button with caption 7 in the Electromagnetic tab of an element or array specification window The current material definition for the component is loaded into the material library dialog whenever it is displayed The contents of the material library are listed on the left side of the Database entries frame Current definition A description of the currently selected database item is displayed here When the dialog box is first displayed this entry will be the same as the Materials entry in the component speci fication window Add to database Pressing this button adds the current material definition to the materials library Select Pressing this button makes the selected item of the materials library to become the current material definition Edit Pressing this button displays a dialog for editing the description of a selected item of the materials library De
231. on button 11 System view drop down list 12 On display drop down list Magsimus status bar 1 1 a F i F Simulation Static Ready Computed time ns 0 2490 57 1109 81 n Fig 6 6 Magsimus status bar The status bar Fig 6 6 displays a variety of useful and informative messages about the state of a design in Magsimus The information provided by the indicated panels of the status bar follows 1 Simulation type Displays the simulation type Static Quasi Static or Dynamic 2 Simulation state Displays Magsimus status messages These messages are described in Table 6 1 3 Computed time The information here is relevant only for dynamic calculations It represents the computed total elapsed physical time 4 Mouse pointer coordinates Displays the x y current mouse pointer coordinates in system design coordinates 5 Equilibrium iteration count Displays the total number of equilibrium simulation states computed since the start of a calculation Table 6 1 Magsimus status messages Message Meaning The motions defined for the design are currently Displaying defined motion being displayed Closing window Please wait A dialog box or other type of window is being closed Loading data Please wait Data is being loaded for use in a dialog box being opened Loading external file Please wait An external design file is being loaded The current display of defined motions was
232. on tolerance This specifies a criterion that defines the extent of magnetostatic interactions with other components in the system see Chapter 5 for more details Calculate array self field due to it s current Checking this box causes the inclusion in calculations of the field component due to the electrical current flowing in the array Use macrospin model Checking this box treats the array as a macrospin The magnetization of the array cells rotate together in unison as a single domain sample and intra array exchange interactions are neglected This model is very useful when used in conjunction with arrays patterned into different shapes User defined Parameters tab Data entry for third party input extensions takes place here Note This feature is not available in current software version Stimuli sources tab The tab shown in Fig 8 7 is used to specify stimuli sources for the component These are temperature profiles of thermal sources and equiv alent magnetization profiles of magneto motive force MMF sources that can be applied to the component When a component is fed by an MMF source its saturation magnetization varies according to the MMF profile These profiles are defined as a sequence of the basic profiles Pulse train and Harmonics The characteristics of these profiles and the manner in which they are defined and managed are similar to those of electrical current profiles discussed under the topic Specifying elec
233. ond Field s Field per nanosecond Field ns Color attributes tab General Options Start up Units Inside the main toolbar and system view frames below double click a colored area or text enclosed by to select background and text color schemes for the corresponding dialog boxes of Magsimus Main toolbar colors System view colors Simul Ctrl Heading Azim lt Rec Ctrl gt ET WINISIec Mode Lis Set to defaults TERA EER Color attributes for new designs G Pinning f View list Comp list A e E Color C Magnetic anisotropy vector C d Set tordefeuke Electrical Circuit lines Set to defaults OK Cancel Help Fig 6 7c Color attributes tab of the Environment Settings dialog Certain color attributes of the Magsimus user interface and system design elements are specified here Fig 6 7c Main tool bar and System view colors areas Within these areas double clicking the frame backgrounds or texts enclosed by the angular brackets lt gt displays dialog boxes that can be used to modify the background colors and text color schemes of the main program tool bars and System view windows in the software These colors come into effect after the Environment Settings dialog is closed Color attributes for new designs area The line colors and widths used in displaying the pinning field vector the mag netic anisotropy vector and electrical circuit li
234. onent can be edited by double clicking on it with the mouse This displays the appropriate editor properties dialog for modifying the properties of the component Right clicking the mouse in the system structure box displays a popup menu that can be used to add delete edit and manipulated the design components in other ways This popup menu is described in the following section The system entry can not be deleted there is always one system in every design To edit the label of an entry first select it by clicking on it once with the mouse pointer then click on it again A cursor appears among the highlighted text which can then be edited Design Manager popup menus The following is the functions of the popup menu items displayed by right clicking the mouse in the system structure box Add Displays a submenu Group Element Array Magnetic shield field array probe for adding a new item to the system A new group is appended at the end of the system hierarchy a new component of a group is appended at the end of the group hierarchy The component properties dialog boxes that are displayed by selecting an item of the submenu are described in Chapter 8 Magsimus Reference Components specification Edit Displays the specification dialog box for the item currently selected in the system structure box Insert component Displays a submenu Group Element Array Magnetic shield field array probe for inserting a new item in the
235. oordinate axes Current is assumed to flow uniformly in the element Magnetic properties Magnet types A magnetic element is uniformly magnetized or single domain Its magnetic state is graphically depicted by an arrow representing the magnetization vector Normal magnet The magnetization vector has a fixed magnitude and is free to rotate in three dimensions under the influence of an external field The magnitude and angular orientation of its magnetization vector characterize such an element e Pseudo soft magnet The magnetization vector is not fixed in magnitude and can rotate freely in three dimensions under the influence of an external field The magnetization is characterized by a relative permeability diagonal tensor and saturation magnetization Permanent magnet The magnetization vector of a permanent magnet element has a fixed magnitude and direction in the element s coordinate frame Non Magnet Does not have a magnetization vector Magnetic anisotropy An element can have a magnetic anisotropy consisting of a collection of independently acting uniaxial and pinning anisotropies Each anisotropy is characterized by an easy axis and anisotropy field strength The magnetization tends to orient parallel to the easy axis under the influence of the anisotropy field The uniaxial anisotropy is bi directional while the pinning anisotropy is unidirectional Exchange An element can be exchange coupled to other elements a
236. or relative In the former case the scale limits of the color wheel are equal in magnitude to the saturation magnetization of the array For relative scaling the maximum and minimum values of the mapping variable calculated from the map on display are used as the limits of the color wheel The following map types can be displayed 1 1 Vectors only Only the projection of vectors is plotted in the vector map box The vectors can be color coded 2 2 Vector on scalar map A vector plot is superimposed on a color coded scalar map This map type is the one in use for the vector map shown in Fig 8 16 3 3 Scalars only A color coded component of the array vector map is plotted Different rectangular areas of the vector map can be zoomed into made to appear bigger as follows Click and hold down the left mouse button on a cell at one corner of the rectangular region Without releasing the mouse button drag the mouse to the other corner of the rectangular region a rubber band box is displayed as the mouse is dragged Upon releasing the mouse the swept out region is displayed to fill the vector map Any number of subsequent zooms can be carried out Double clicking the vector map returns it back to the un zoomed state Plane options Selecting any of the options u v v w or u w causes the projection of the array magnetization on the corresponding plane to be plotted The labels for the planes follow a horizontal vertical conve
237. ou then collate them in the Batch Job Manager and execute them in sequence Each of the defined simulation is saved to file when its execution is complete Batch Job definitions are saved in batch files with file extensions mbat Descriptions of the numbered controls in Fig 6 10 follow 1 Open new batch job Pressing this button loads in a new batch job file 2 Save batch job Pressing this button saves the current batch job to file fl Batch job manager Simul 1 26 03 mb m fa px le M Head over Longitudinal media 1 mus mr read head concept mus ET Logol mus Iv Run jobs in background Create a Recording Carousel Fig 6 10 Batch Job Manager window 3 Skip forward Pressing this button skips to the next file in the batch sequence during the execution of the batch job 4 Run Pressing this button initiates the execution of the batch job sequence The execution can be paused or stopped by pressing the Pause or Stop buttons in the simulation controls of the System view window 5 Skip backward Pressing this button skips to the previous file in the batch sequence during execution of the batch job 6 Add item Pressing this button adds a new design file to the batch job Multiple items can be selected at once in the displayed Windows file open dialog box 7 Delete item Pressing this button deletes selected design file of the batch job 8 Help 9 List of design files contained in the carousel Double clicking
238. ous group Relative to the system origin can be selected Component This is a drop down list from which group options Relative to the previous component Relative to the group origin can be selected Start up Units tab General Options Color attributes Calculation control Electrical Magnetic cas Y Current Miliampere m v Length Nanometer nm v Voltage Millivolt mv Ne Dynamic time rates Time Nanosecond ns Linear velocity m s Force Nanonewton nN Angular velocity Dea s Set to defaults Field sweep rate ield s v OK Cancel Help Fig 6 7b Start up Units tab of the Environment Settings dialog The default computational units for a new Magsimus design are specified here Fig 6 7b The units are selected from the following lists Magnetic CGS SI Length Nanometer nm Micrometer um Centimeter cm Meter m Inch in Microinch uin Time Nanosecond ns Second s Force Nanonewton nN Micronewton uN Newton N Kilonewton kN Current Milliampere mA Microampere uA Ampere A Voltage Millivolt mV Microvolt uV Volt V Linear velocity Meter per second m s Meter per nanosecond m ns Inch per second in s Inch per nanosecond in ns Angular velocity Degree per second Deg s Degree per nanosecond Deg ns Revolutions per minute rpm Field sweep rate Field per sec
239. pecification dialog 191 in Lines and Colors tab of magnetic shield specification dialog box 203 in Lines and Colors tab of Probe specification dialog 197 Linear dimensions along coordinate axes frame 23 25 33 Linear Network Analysis 96 linear shield model 73 linear soft magnet 55 Linear velocity list in Start up Units tab dialog of Environmental Settings dialog 117 Lines and Colors System display pane action menu 143 Lines and Colors tab 23 24 LL See Landau Lifschitz Gilbert LL equation LLG equation See Landau Lifschitz Gilbert equation LLG See Landau Lifschitz Gilbert LLG equation Lock Components button 29 Lock controls in main program lower toolbar 147 Lock system geometry at start of a simulation option in General Option tab dialog of Environmental Settings dialog 114 Lock Unlock button 140 long range interaction field 75 Loop external field leg 155 Loops 230 Low pass option in Spectral filter settings dialog box 211 Low pass X floating sub menu item of 2 D curve window 210 Low pass X Y floating sub menu item of 2 D curve window 210 Low pass Y floating sub menu item of 2 D curve window 210 M vector field color guide System display pane action menu 144 macrospin 193 Macrospin behavior array magnetic properties 62 MagJob job scheduling and monitoring utility 12 13 Mag Job utility application 52 Magnet Type list in Electromagnetic tab of Array specification dialog 182 Magnet type list 25 33
240. polar angle of the selected item This entry can also be modified using the scroll bar beneath it Chapter 8 Magsimus Reference Component specifications Introduction This chapter rounds out the reference description of Magsimus user interface elements The main program and System view windows are discussed in Chapters 6 and 7 In this chapter the treatment will include a description of the following e System group and components properties specification dialog boxes Array patterning dialog box e Data output windows Specifying electrical circuits Specifying the properties of the system object The component hierarchy of a Magsimus design consists of only one system object This object is represented by the root node in the System structure list see the topic Integrated Design Manager in Chapter 7 The dialog box for specifying its properties can be displayed by one of the following methods 1 Selecting the main program menu item Special System specifications 2 Double clicking the mouse on the root system icon in the System structure list 3 Right clicking the mouse on the root icon in the System structure box and selecting Edit in the displayed floating menu 4 Double clicking the mouse anywhere in the System display pane away that does not fall within a group or component bound and therefore would not select them as a result The system specification dialog box is used for specifying system wide des
241. portional to the magnitude of the neighbor s magnetization that is from zero to a maximum value equal to the coupling field specified here See Chapter 5 for more information on exchange couplings Note The definition of exchange applies only to the target component Definition of exchange couplings is irrelevant in the calculations of non magnetic and permanent magnetic arrays There are no limits to the number of couplings that may be defined Any number of couplings with the same component and even of the array being edited with itself are permitted Coupling field within array or Exchange A param within array Specifies exchange coupling fields between the array cells Along u Along v Along w Coupling between elements area Field or Exchange param A Specifies the exchange coupling field between the array and the component currently being exchange coupled to The field is expressed in Oe in the CGS system of units or in kA m in the SI system of units Exclude magnetization dependence option Checking this box neglects the dependence of the computed exchange field term on the magneti zation of the coupled neighbor Apply cell to cell coordination in calculations this is applicable only when two array components are coupled to each other Check ing this box causes the coupling of the components be between the correspond ing cells of the arrays Use interface coupling option This input is relevant when cou pling is
242. posite current profile formed from a sequence of independent current legs I legs A full description of the dialog box is available through the online help Electrical current profile types are described in Chapters 5 Here we define a profile with one I leg and describe only those actions necessary to proceed with the ongoing design Make sure the entry Pulse Train 1s selected from the I Type drop down list then press the Add button Enter the following data Signal pattern 1010 Max current level mA 5 Min current level mA 10 No rise time steps 0 No fall time steps 0 No pulse duration steps 10 Complete the definition of the current profile by pressing the OK button Exit the Group specification dialog box by pressing its OK button Show the defined circuit in the system display plane as follows Right click the mouse in the system display pane and from the displayed popup menu click Set system display attributes gt Show Electrical Circuits Specifying motion Motion is defined for groups The group moves as one whole with its coordinate frame The relative locations and orientations of the compo nents of the group in its coordinate frame are preserved during motion Let us define motions for the groups Probe holder and Biased field source The motion for the probe holder will be a rotation about the group of electrically energized nonmagnets while the biased field source will undergo a two stage translation motio
243. pplies only to array components Displays a dialog box that enables the patterning of the array that has been selected in the system structure box Patterning entails the turning on and off of the magnetic properties of selected cells of the array See Chapter 8 Magsimus Reference Components specification for a discussion of this dialog box Zoom near group applies to the selected group node in the Design Manager This causes display of the design in the System display pane to be zoomed about the limiting extents of the group Zoom near component applies to the selected component node in the Design Manager This causes display of the design in the System display pane to be zoomed about the limiting extents of the component External Field Controls The External Field Controls Fig 7 4 provide the means for applying an external field to the system A perspective view of the currently active external field vector is displayed by an arrow in the Field display pane the box containing the XYZ axes in Fig 7 4 This field will be one that will act on the design during a simulation External Field Controls v es p D Field Mode Scale Oe H Oe eee Azimuth Deg fs 4 gt Polar Deg i i Fig 7 4 External Field Controls in System view window Values at all data fields of the external field controls corresponds to the field on display at the field pane A field sequence composed of field egs
244. profiles motions and externally applied fields are given in terms of a finite number of incremental steps During the calculation the solver advances these definitions one step at a time In this example the rotary motion of the field probe and the first glancing motion leg of the biased field source ends after 20 steps From then on the probe remains stationary while the bias field source continues with its second motion leg which is a series of horizontal displacement to the right when the design is viewed from the front Both the electric currents feeding the first group and the external field applied to the system continually change all along The duration of the external field variation eventually outlasts that of the electric current profile When the defined duration of the electrical current profile elapses the current source simply supplies a steady current equal to the value at which the signal profile terminated The first group being composed of non magnets is oblivious to changing magnetic fields The magnetic state of the permanent magnet of the biased field source is also unaffected by the magnetic fields The magnetic state of the array of cells however changes with applied field which is a combination of the externally applied field the field produced by currents in the first group and the field produced by the permanent magnet of the moving biased field source Wait for the simulation to end the status bar will read Ready
245. ps oque Signal type Pulse train No fall time steps o Add No pulse duration steps fi 0 Delete Preview signal Clone Clear All No Quasi Static sample points OK Cancel Help Fig 8 7 Stimuli sources tab of Array specification dialog box Probe Specification dialog box Geometry tab Probe Specification 1 2 Field probe Data Output Lines and Colors Component origin in group coordinate system nm Input type Relative to the previous component x Cancel Help Fig 8 8a Geometric tab of Probe specification dialog The coordinate origin of the probe within the coordinate frame of the parent group is defined here Fig 8 8a See Chapter 4 for additional information on the coordinate system of design components Component origin in group coordinate system Specifies the location of the origin U V W of the component in its group The selection in the Input type box Relative to previous component Relative to the group origin determines how the origin input is to be interpreted The default input type can be specified in the in environment dialog box reached by selecting the main program menu item Special gt Environment settings Lines and Colors tab El Probe Specification 271 Field probe x Data Output Probe outline Line Thickness z OK Cancel Help Fig 8 8b Lines and Colors tab of Pr
246. pter 4 An element may be magnetic or nonmagnetic a conductor or an insulator An array is a collection of elements defined on a rectangular grid The elements of an array are referred to as cells A field array is a rectangular array of points that is used for visualizing interaction field regions in space It does not represent a physical material object but a construct of points The interaction fields that can be visualized are the magnetostatic fields produced by the polarization of magnetized objects as well as magnetic fields produced by currents flowing in the system Each field point is centered within a cell region defined similarly as for a material array A magnetic element is uniformly magnetized or single domain Its magnetization is represented by a single vector drawn as an arrow Each magnetic element may be a normal magnet a pseudo soft magnet or a permanent magnet The magnetization vector of a normal magnet is fixed in magnitude but is free to rotate in three dimensions For a pseudo soft magnet both the magnitude and direction of the magnetization vector can change The magnitude and direction of the magnetization vector of a permanent magnet remain fixed relative to the element Coordinate systems Various Cartesian coordinate frames are defined to facilitate the description of the system geometry These are the system coordinates XYZ the local group coordinate UVW and the local coordinates of the components
247. ration distance traveled and time Iteration refers to the cumulative iteration count of the calculation measured from the onset of the simulation It serves as a ticker that measures the progress of the simulation The user can specify both equilibrium and non equilibrium output If this is not the case then the iteration count applies to a sequence of equilibrium states Distance traveled refers to the distance covered by the component as a result of its motion from the start of the simulation The distance is calculated for linear translation motion alone and does not take into account the rotary motion of the component Time output is the calculated elapsed physical time that is measured from the beginning of the simulation All three outputs are interpreted similarly for all design components Magnetization and Magnetic Induction For a magnetic element the magnetization output is the instantaneous magnetization vector of the element For normal and permanent magnets the magnitude of this vector is equal to the saturation magnetization of the element The direction of the magnetization of a permanent magnet is fixed in the element s coordinate frame The magnitude of the magneti zation vector for a pseudo soft magnet varies between zero and the saturation magnetization Non magnets have no magnetization vectors The magnetization vector output of an array is calculated as the average magnetization vector of its cells The total magnetization
248. rcuit tab of System specification dialog 168 constant current source 66 221 contact area of electrical contact leads 176 Contact definition swatch in Electrical contact properties dialog box 178 Context sensitive online help 227 context sensitive See Online help convergence tolerance 70 Convergence tolerance box in Calculation tab dialog of System specification dialog 165 cooperative effects 72 Coordinate system s 19 57 Copyright 243 246 Couple new component button in Magnetoresistance tab of Array specification dialog 190 Coupling between elements area in Exchange Coupling tab of Array specification dialog 187 Coupling field within array in Exchange Coupling tab of Array specification dialog 187 Coupling plane area inter element coupling in Exchange Coupling tab of Array specification dialog 188 Create a recording carousel button in Batch Job Manager 126 curl in 2 D Vector Map window 216 217 Current box in parametric output window 214 Current definition box in Material library dialog 220 current legs 37 Current list in Start up Units tab dialog of Environmental Settings dialog 117 current shunting 85 Current source area in Electrical Circuit tab of group specification dialog 173 in Electrical Circuit tab of System specification dialog 168 Current Source frame 37 Current density map floating menu displayed in the System Display pane 216 System display pane action menu 145 current vol
249. rcuit tab of group specification dialog 173 174 Directories button in Importing components window 225 Disallowed modules area Magsimus About dialog box 108 Discretize menu in integrated Design Manager 135 Display group s field panel check box in system external field specification dialog 151 Displayed component list 34 distance traveled 82 divergence in 2 D Vector Map window 216 217 domain wall motion 88 Download software updates Main program menu item 107 Drive button in Importing components window 225 Duration box in Pulse external field definition dialog box 157 Duration of motion in Motion tab of the Group specification dialog 175 Duration steps box in Pulse external field definition dialog box 157 duration td 67 Dynamic in Calculation tab dialog of System specification dialog 164 dynamic 69 72 228 dynamic conditions 8 Dynamic equation properties area in Calculation Control tab of Array specification dialog 192 dynamic method 19 Dynamic properties of elements 61 Dynamic Solver 70 E easy axis 80 185 Edit 46 Edit button 41 150 in External Field Controls 137 in Material library dialog 220 Edit elect contacts in Electrical Circuit tab of group specification dialog 173 Edit electrical contacts button in Electromagnetic tab of Array specification dialog 183 Edit junction button in Electromagnetic tab of Array specification dialog 183 Edit M color wheel System display pane action menu
250. re in the plot window For more on the floating menu refer to the section 2 D Plot window of Chapter 8 The transforma tions are as follows 1 Integral This is the integral of the Y data set as a function of the X data set The trapezoidal rule is used to compute this integral The last Y data point represents the total algebraic area enclosed by the base curve 2 Derivative This is the derivative of the normal Y data set as a function of the X data set The secant rule is used to compute this derivative 3 X and Y Fourier spectra This is the Fourier decomposition of the normal X or Y data set The original data set is re sampled into a new set numbering an appropriate power of 2 before the transformation is carried out The Fourier transform in general results in a functional set of complex numbers versus integral harmonics whose characteristics can be individually plotted 4 Spectral filtering This is the inverse transformation of Fourier data by suppressing selected frequency harmonic components Filtering of X and Y data sets individually or simulta neously can be carried out Low pass filtering suppresses harmonics that are in absolute value larger than a prescribed threshold harmonic while high pass filtering suppresses components below a threshold value In band pass filtering spectral components that lie outside the range bounded by prescribed maximum and minimum threshold values are suppressed Ite
251. re protected by copyright laws and international treaty provisions No title to intellectual property is being transferred You may not modify reverse engineer decompile or disassemble the SOFTWARE No warranty The SOFTWARE is provided as is MagOasis does not warrant that the SOFTWARE will meet your requirements or that its operation will be uninterrupted or error free The entire risk as to the quality and performance of the SOFTWARE is borne by you Should the SOFTWARE prove defective you and not MagOasis assume the entire cost of service and repair MagOasis makes no representations warranties or conditions expressed or implied including but not limited to noninfringement conformity to any representation or description merchantability or fitness for a particular purpose or those arising by statute or otherwise in law or from a course of dealing or usage of trade Some jurisdictions do not allow exclusions of an implied warranty so this disclaimer may not apply to you and you may have other legal rights that vary by jurisdiction This disclaimer constitutes an essential part of the Agreement Limitation of Liability NOTWITHSTANDING ANY OTHER PROVISION OF THIS AGREEMENT YOU AGREE THAT MAGOASIS SHALL NOT BE LIABLE UNDER ANY LEGAL THEORY INCLUDING TORT CONTRACT OR OTHERWISE FOR ANY DAMAGES INCURRED BY YOU INCLUDING BUT NOT LIMITED TO DIRECT OR INDIRECT DAMAGES FOR LOSS OF GOODWILL LOSS OF DATA BUSINESS PROFITS BUSINESS INTER
252. reement is declared by a court of competent jurisdiction to be invalid illegal or unenforceable such provision shall be severed from this Agreement and the other provisions shall remain in full force and effect Should you have any questions concerning this license agreement or if you desire to contact MagOasis for any reason please e mail MagOasis at info Magoasis com Demonstration Evaluation license agreement The following license applies to you if you have not purchased Magsimus Deluxe Magsimus Custom Application or other MagOasis software and are using it in its demonstration mode or if an Evalu ation license has been extended to you by MagOasis LLC This is a legal agreement between you Licensee either an entity or an individual the end user and MagOasis LLC MagOasis Please read the following terms and conditions before using this software In the event that you use this software you are agreeing to be bound by the terms and conditions of this agreement Should you not agree with these terms do not use this software License Grant You are granted a non exclusive right to the use of this MagOasis software program SOFTWARE at no cost or obligation to you Documentation in electronic or other format accompanying the SOFTWARE DOCUMENTATION may also be provided to you You may copy and distribute The DOCUMENTATION accompanying the SOFTWARE Copyright This SOFTWARE and the DOCUMENTATION are owned by MagOasis and a
253. replay and analysis Forward reverse recording playback Manual auto auto repeat playback modes Carousel playback of multiple recordings Batch job submision and background job management Submit simulations singly or as a batch in the foreground or background Background job monitoring and control by means of an advanced background job monitor Outputs Native and user defined outputs Over 1500 possible distinct outputs for each design component Magnetization magnetoresistance electrical current and voltages energy den sities force etc Software management resources Automated software version control and updates Automatically receive timely software upgrades over the internet as soon as they become available Flexible licensing options Internet based soft key licensing Autonomuous hard key license Appendix B Data output categories Data output for groups elements arrays and probes that are to be generated during a simulation are specified in the data output tabs of their respective properties specification windows See the section Speci fving and displaying data outputs of Chapter 6 The data categories for the various component types are summarized in the following tables The mathematical description of the calculated outputs is provided by Chapter 5 Mathematical Theory Table 1 1 Data output Categories for groups Data Category Data type Distance General Iterations Time X component of magne
254. rge map box is an illus tration of the layout of the shield face relative to its local coordinate frame Next to this is a color wheel color scale that maps the charge values to colors on the charge map The color wheel includes annotations for the scale limits Clicking and holding the left mouse button on a panel in the vector map box displays information about its charge magnitude on the dialog box caption Clicking anywhere on the charge map box with the right mouse button displays a pop up menu that can be used to print the map save its data to file turn on and off panel outlines edit the color wheel and select the method for scaling the color wheel The scaling method can be absolute or relative In the former case the scale limits of the color wheel are equal in magnitude to the saturation magnetization of the shield component For relative scaling the maximum and minimum values of the mapping variable calculated from the map on display are used as the limits of the color wheel Different rectangular areas of the charge map can be zoomed into made to appear bigger as follows Click and hold down the left mouse button on a cell at one corner of the rectangular region Without releasing the mouse button drag the mouse to the other corner of the rectangular region a rubber band box is displayed as the mouse is dragged Upon releasing the mouse the swept out region is displayed to fill the vector map Any number of successive zo
255. ric tab of Magnetic Shield specification dialog 199 Along w box 32 array matrix dimension in Geometric tab of Array specification dialog 181 coupling field within array in Exchange Coupling tab of Array specification dialog 187 spacing length in Geometric tab of Array specification dialog 181 spacing length in Geometric tab of Magnetic Shield specification dialog 199 Always calculate to full relaxation option in Calculation control tab dialog of Environment Settings dialog 120 Always express exchange using frame in General Option tab dialog of Environmental Settings dialog 115 Always flag new designs for background job submission in General Option tab dialog of Environmental Settings dialog 114 Ampere A 117 Amplitude floating sub menu item of 2 D curve window 211 Fourier component in Plot settings dialog box 212 amplitude of harmonic 68 Ang Velocity box in Rotation external field definition dialog box 156 Angular Coordinates of group orientation in system frame in Geometry tab of Group specification dialog 171 angular momentum 71 Angular orientation coordinates within group frame 25 in Geometric tab of Array specification dialog 181 in Geometric tab of Magnetic Shield specification dialog 198 Angular velocities of rotation frame 39 in Motion tab of the Group specification dialog 176 Angular velocity list in Start up Units tab dialog of Environmental Settings dialog 117 Anisotropic magnetoresistance AMR 228 ou
256. ries Magsimus Deluxe offers a means of specifying if a GMR coupled component can scatter minority spins Scattering is characterized by a user specified reflection coefficient 0 lt I lt 1 that repre sents the reflective quality of the scatterer The resulting effective field formula for this effect is similar to the ones used in 29 and 30 with the following modifications made 1 The negative sign is replaced by a positive sign in the new equation to indicate that momentum transfer are now due to electron spins of opposite polarity 2 The equations are pre multiplied by the reflection coefficient r and a new reflection polarization factor P 1 P is used in place of P 3 The selected neighbors in the summation are those for which traceable negative current paths exist between them and the target Note As with everything SMT this aspect of it is still somewhat evolving on many fronts and is the subject of competing mainly non phenomenological theories in the literature Our present imple mentation is likely to change over time Anisotropic magnetoresistance AMR Anisotropic magnetoresistance AMR is another manifestation of the magnetoresistive effect of a different physical origin than the giant magnetoresistance described above It occurs when the magnetization of a component changes direction relative to the current flowing through the component Refer to the literature for a more detailed discussion of this phenomenon an
257. ring of the components in the figure are for illustrative purposes they are not generated by the software Objects 4 and 6 will move around in space during the simulation The objects are following the numbering in the figure 1 Electrical current source 2 Non magnetic element 3 Non magnetic element Elements 2 and 3 are connected electrically in parallel and supplied by current source 1 4 A field probe 5 An array of normal magnetic elements cells 6 A permanent magnet fl MagSimus Deluxe TestDesign mus Fie Special Window Hep fl System view Test design IV Use field definitions Edi of i ie Loop Scale 0e 00 H Oey oo fie EER Simulation Static Ready Computed time s 0 Fig 3 2 First design example About Design components The creation of a new design involves assembling a system composed of several functionally distinct groups that are made up of basic design components These components are elements arrays of elements probes shields and field arrays An element and a shield have shapes in the form of rectangular prisms Shields and field arrays will not be part of the design we describe in this section A complete discussion of the concept of a system groups and basic components is given in Cha
258. rmination of this agreement as shall all provisions regarding payments of amounts due at the time of termi nation This agreement shall be governed by the internal laws of State of Texas USA Should Licensee install the SOFTWARE outside the United States Licensee shall comply fully with all applicable laws and regula tions relating to the export of technical data This Agreement is the entire agreement between MagOasis and you supersedes any other agreements or discussions oral or written and may not be changed except by written amendment signed by MagOasis This Agreement shall be governed by and construed in accordance with the laws of the state of Texas USA excluding its conflict of laws rules and the United Nations Convention on Contracts for the International Sale of Goods If any provision of this Agreement is declared by a court of competent jurisdiction to be invalid illegal or unenforceable such provision shall be severed from this Agreement and the other provisions shall remain in full force and effect Should you have any questions concerning this license agreement or if you desire to contact MagOasis for any reason please e mail MagOasis at info Magoasis com MagOasis Hard key Policy We warrant the hard keys we provide you with as part of an initial product shipment against any defects for the first 30 days after they are delivered to you During this period you are eligible for a one time swap per defective key with a
259. rop down list of the components in the system the entire system groups and the components of a group Selecting an item from this list displays only that item in the system display pane The first item on the list is the whole system the remaining entries follow the order of items in the system as in the Design Manager Each component entry is preceded by its designation according to Magsimus component numbering scheme see the section Components numbering scheme in Chapter 4 13 Help button Rotating Components Group Component Azimuth angle Dea 38 E n Polar angle Deg 23 Help E I 2 Fig 7 10 Dialog box for rotating design components The groups and design components of Magsimus can be oriented at any angle in three dimensional space relative to each other The angular orientation coordinates of components can be specified in their properties dialog boxes described in Chapter 8 A component that is selected in the System display pane may also be interactively rotated by pressing the Rotate button in ths System display tool bar Fig 7 9 This action displays the Rotating component dialog box shown in Fig 7 10 Groups are rotated relative to the system coordinate frame while the components of a group are rotated relative to the group coordinate frame The displayed design is continuously updated to reflect the changes made in this dialog box Chapter 4 provides a description of coordin
260. rrent Specifies that a constant current source is connected to the source element The input box to the right is used to enter the output cur rent of the current source in milliamperes Custom current profile Specifies that a variable current profile is connected to the element Clicking the box to the right displays a dialog boxfor specifying custom current profiles This dialog box is described below under the topic Specifying electrical current signals Source exit component Specifies the component whose negative ter minal is connected to the defined current source Connections to other components area This area contains the means of specifying the circuit properties of the destination component Towards the right are a set of check boxes for accomplishing the connection of source and destination components Straight lines connecting the check boxes provides visual guides for determining the manner of connections As these boxes are checked the resulting connections are displayed in the Group circuit diagram box Destination component Drop down list containing the connectable components of the group Selecting a component from this list defines it as a destination component An icon appropriate for the type of selected component is displayed to the right Direction of current Specifies the destination component axis U V or W along which current will flow in the component Specifying Motion l Group Specification
261. s Lw nm New Group Component zx Fe cube Start value 250 End value 500 No of sweeps fi Fig 7 12 Parametric simulation tab A parametric simulation is one that is repeated several times using different values of certain design properties parameters which are varied systematically The process of varying a parameter is called sweeping of the parameter The design parameters to sweep and the range over which they are to be varied are specified under this tab Fig 7 12 Graphical plots for parametric simulations are in the form of surface plots Generate parametric data Checking this box enables the gener ation of parametric data during a simulation Parameter category option Indicates the type of design feature Component Group External field whose parameters are to be varied Component in this context refers to a single element an array a probe or a shield For the External field option the parameters to vary may be defined for any number of the legs of the field sequence Group This is a drop down list of the groups in the system Selecting an item here identifies it as the group to refer to in the parametric calcula tions If the Group option was chosen as the parameter category the variation of parameters will occur for the group selected from this list Component This is a drop down list of the components of the group selected in the Group list If the Component option was cho
262. s normally used to realize domain wall motion in the former structures To simulate SMT for a single layer film the corre sponding component must be defined as being GMR coupled to itself In this case the magnetization summation in 29 is over appropriate nearest neighbor cells of the target cell that is those neighbors whose local current density vectors are directed away from the target The spin torque effect is a purely dynamic phenomenon However Magsimus provides the following formal extension of the effective field term for static and quasi static calculations N gmr Ho hre X Pim 30 where h gt 0 is a user supplied SMT field per current parameter which may be estimated using 29 Note SMT phenomenon is a relatively new topic While the implemented model is currently the most prevailing in the scientific community this field continues to evolve There is therefore the possibility that this formulation may become in need further refinements in the future Minority spin reflection effect Magsimus Deluxe provides a means for accounting for another form of SMT due to reflected back scattered minority polarized electrons at component boundaries This model is applicable to inter component interactions alone not to self SMT interactions In this treatment consideration is given to the role of electron flux moving away from the target cell as the ones that are eventually scattered at the coupled component bounda
263. sen as the parameter category the variation of parameters will occur for the item selected from this list Parameters area Source This is a list of all parameters whose values can be varied in a simulation for the currently defined parametric run An item from this list can be made part of the Target list by double clicking on it The parameters listed Target This is a list of those parameters selected from the Source list that will be varied during a parametric simulation Pressing this button transfers a selected parameter in the source list to the target list Pressing this button removes a selected parameter from the target list Start value This specifies the initial value during a simulation of a parameter selected at the target list End value This specifies the final value during a simulation of a parameter selected at the target list No of sweeps This specifies the number of increments of the target parameters from their initial values to their final values External field type inputs Magsimus provides a variety of external field leg types that can be chained together to specify complex vector field sequences to be applied to the system The field types are selected under the External field specs tab of the external field specification dialog box Fig 7 11 A data specification area in this tab is reconfigured with appropriate input fields that is applicable to the selected field type The field types and
264. sfer this selection to the Target box by clicking on the left transfer button above the Target box This parameter appears in the target box Fig 3 14 The Target box lists all the parameters that will be varied during the simulation To remove a parameter from the target list first select it in the list and then press the right transfer button above the Target box Select our one parameter in the target list and make the entries Start value 0 End value 90 No of sweeps 10 Exit the simulation specification dialog by pressing the OK button Commence the simulation by pressing the Run Simulation button in the main program tool bar After a few moments the parametric output window is displayed Fig 3 15 This window may at first be minimized restore it to its normal size in that case A parametric output window is launched for each specified output Observe how different M H loops are traced out as a function of field direction during the simulation Right clicking on any of the plot windows brings up floating menus that can be used to further work with the plotted data The surface plot generated by the simulation is displayed in the Parametric plot box Bring up the floating menu of this box and select the menu item Show Cut A cutting plane of the surface appears in the box and a two dimensional plot of the cut points is displayed in the Cut trace box Change the orientation of the cutting plane by selecting any of the options X Y
265. stem display pane action menu 145 Perspective view button in main program lower toolbar 148 Phase floating sub menu item of 2 D curve window 211 Fourier component in Plot settings dialog box 212 phenomenological GMR theory 84 physical time 111 pin holes in magnetic tunnel junctions 91 pinning anisotropy 79 228 pinning fields 7 Pinning option magnetic anisotropy in Magnetic Anisotropy tab of Array specification dialog 185 Plane options in 2 D vector window 218 in array patterning dialog box 205 Play button in Recording playback Carousel 123 Plot data markers for new output curve plots in General Option tab dialog of Environmental Settings dialog 115 Plot settings dialog box 211 Plot type floating menu item of 2 D curve window 210 Plot type frame in Plot settings dailog box 212 Polar orientation angle in Geometric tab of Array specification dialog 181 orientation angle in Geometric tab of Magnetic Shield specification dialog 198 Polar angle box 42 47 in Loop external field definition dialog box 155 in Rotating Component dialog box 149 Polar angle range area in Rotation external field definition dialog box 156 Polar box 25 33 39 40 46 angular velocity definition in Motion tab of the Group specification dialog 176 Easy axis orientation in Magnetic Anisotropy tab of Array specification dialog 185 in External Field Controls 138 magnetic vector distribution in Electromagnetic tab of Array specification dialog 183
266. system at the position of the current selection in the system structure box The Group entry appears in this submenu only if a group icon was selected in the system structure box The component properties dialog boxes that are displayed by selecting an item of the submenu are described in Chapter 8 Magsimus Reference Components specification Import component Displays the import component dialog that is used to import components of external designs into the current design See the The groups of the imported designs are appended to those of the current design See Chapter 8 Magsimus Reference Components specifi cation for a discussion of this dialog box Delete Deletes the item currently selected in the system structure box The user is prompted to confirm the deletion before proceeding Clone Creates an exact replica clone of the selected item in the system structure box and appends it to the system design Discretize Applies to non array non probe and non shield compo nents Displays the Discretize element dialog box shown in Fig 7 3 for specifying the matrix dimensions in array cells for the array into which the element will be transformed LL Discretize element inl xj Specify array dimensions number of elements Along U axis Ie Along V axis 2 Along W axis 2 OK Cancel Fig 7 3 Dialog that is displayed at the start of discretizing an element in the integrated Design Manager Pattern array A
267. t is used to specify the properties of a new probe of the group that was selected in the System Structure list 6 Add field frray Pressing this button displays the field array specification dialog box that is used to specify the properties of a new field array of the group that was selected in the System Structure list 7 Import external components Pressing this button displays the import component dialog that is used to import components of external designs into the current design See the The groups of the imported designs are appended to those of the current design See Chapter 8 Magsimus Reference Components specification fora discussion of this dialog box System structure box The system hierarchy of a design is defined visually displayed and maintained in the system structure box of the Design Manager The system and its components are listed in this box The entries of the list are appropriately indented to reflect the system hierarchy Identifying icons for the primitive types accompany each entry of the list Remarks The design shown in Fig 7 2 is of a system named System example that is composed of two groups Group with many compo nents and Group with just one element The components of the first group are representative of all possible component types the names of the components in the figure have been chosen to identify their types The second group consists of just one element New Element1 Any listed comp
268. t output curve lines and colors in dialog for specifying output data for a group 207 Set selected component display attributes System display pane action menu 142 Set system design attributes System display pane action menu 141 shape anisotropy 75 Shield charge map System display pane action menu 145 shield charge maps 227 Show Hide iteration update panel System display pane action menu 141 Show array M color wheel System display pane action menu 143 Show Axes Floating menu in parametric output window 214 Show Component Labels System display pane action menu 142 Show Component outlines System display pane action menu 142 Show Coordinate Axes System display pane action menu 141 Show Coordinate axes check box in Importing components window 226 Show current density vectors System display pane action menu 141 Show Cut Floating menu in parametric output window 214 Show Cut box 48 Show data markers check box in Plot settings dialog box 213 Show Electrical Circuits System display pane action menu 141 Show equilibrium magnetic states box in Calculation tab dialog of System specification dialog 165 Show Grid Floating menu in parametric output window 214 Show input contact tab box in Electrical contact properties dialog box 177 Show iteration states check box in Calculation tab dialog of System specification dialog 165 Show Mag Anisotropy axes check box in Importing components window 226 Show Magnetic Anisotropy Axes Syste
269. tab is discussed under the topic Specifying output data Geometry tab Group Specification 1 MRAM Device Group Geometry Group origin in system coordinate frame nm Input type Relative to the previous group xf 2 0 zo Angular Coordinates of group orientation in system frame Deg Azimuthal 0 Polar 0 Cancel Help Fig 8 2a Geometry tab of Group specification dialog The geometric location of the group being specified is defined under this tab Fig 8 2a Chapter 4 discusses group coordinate systems further Group origin in system coordinate frame Specifies the coordinates of the origin of the group X Y Z in the system coordinate frame The selection in the Input type box Relative to previous group Relative to the system origin deter mines how the origin input is to be interpreted The default input type can be specified in the in environment dialog box reached by selecting the main program menu item Special gt Environment settings Angular Coordinates of group orientation in system frame Specifies the angular orientation coordinates Azimuthal Polar of the group in the system coordinate frame Electrical Circuit tab The electrical circuit for the group currently being edited is defined here Fig 8 2b The circuit is defined by specifying the electrical connections between design components making up the group elements or arrays group level electrical current sources and their co
270. tage I V characteristics 94 Custom current profile option 37 in Electrical Circuit tab of group specification dialog 173 in Electrical Circuit tab of System specification dialog 168 custom current source 66 221 Cut trace box 48 in parametric output window 214 D damping 71 damping constant 61 Damping constant box in Calculation Control tab of Array specification dialog 192 damping factor 71 damping term 71 Data Category box 26 Data category list in dialog for specifying output data for a group 206 Data markers frame in Plot settings dialog box 213 Data output dialog box 206 Data Output tab 26 31 32 46 Data output windows 208 data recovery 52 Data to filter box in Spectral filter settings dialog box 211 Data type box 26 Data type list in dialog for specifying output data for a group 206 DataBase application subdirectory 238 Database entries frame in Material library dialog 220 Daughton J M 85 96 Decker S K 97 Default input types for geometric origins in General Option tab dialog of Environmental Settings dialog 115 Define New button 46 in Magnetic Anisotropy tab of Array specification dialog 185 inter element coupling in Exchange Coupling tab of Array specification dialog 188 Delete button in dialog for specifying output data for a group 207 in Electrical contact properties dialog box 178 in Magnetic Anisotropy tab of Array specification dialog 185 in Material library dialog 220 in system externa
271. tation angle in Geometric tab of Array specification dialog 181 198 Azimuthal box 25 angular velocity definition in Motion tab of the Group specification dialog 176 Easy axis orientation in Magnetic Anisotropy tab of Array specification dialog 185 magnetic vector distribution in Electromagnetic tab of Array specification dialog 183 velocity angle in Motion tab of the Group specification dialog 175 back view of design 148 Background job monitor Main program menu item 107 background job monitor 127 background jobs 126 230 background processes 52 Balabanian N 65 96 Band pass option in Spectral filter settings dialog box 211 Band pass X floating sub menu item of 2 D curve window 210 Band pass X Y floating sub menu item of 2 D curve window 210 Band pass Y floating sub menu item of 2 D curve window 210 Base field box in Pulse external field definition dialog box 157 base fields in 2 D Vector Map window 216 Batch Job Manager 52 106 124 238 Main program menu item 106 Batch job s 230 238 Berger L 87 96 Bertram H N 97 Bibliography 96 bi directional anisotropy 79 Boit Savart law 78 bottom view of design 148 Brown W F 68 96 C CAD 227 Calculate array self field due to it s current in Calculation Control tab of Array specification dialog 193 Calculate surface charges for all faces in Electromagnetic tab of Magnetic Shield specification dialog 200 Calculate to full relaxation
272. te system uvw is associated with the whole array The location of the coordinate origin within the parent is treated similarly as for an element see above The array size is determined by the linear dimensions of its cells having similar characteristic lengths as elements discussed above and by the size of the array matrix or grid given by the number of cells along each coordinate direction in the array layout The angular orientation of an array is specified similarly as for an element see above Electrical properties The array is characterized by an electrical conductivity and electrical current can flow through it in a direction that is parallel to one of its coordinate axes Current may not flow uniformly in an array due to geometric and material inhomogenieties among it cells Magnetic properties Magnet types Arrays cells can be of the same magnet types as elements An arrow is used to depict the magnetization vector of a cell Magnetic anisotropies When specified for an array the anisotropy definitions apply to all cells of the array The easy axis distribution for an array is specified by giving the mean angular coordinates and angular standard deviations of the anisotropy axes Remarks Exchange magnetoresistance and dynamic properties are all defined similarly as for elements see above In addition the array can becharacterized by an intra layer exchange coupling between its cells Macrospin behavior An
273. ted See the section Tip of the day window below for a description of this dialog Enable simulation check pointing for new designs option Checking this box will ensure that the simulation check pointing property will be turned on for all new designs Enable end of simulation geometric reset for new designs option Checking this box will ensure that the initial geometric properties dimensions and positions of a design at the beginning of a simulation are restored at the end of the simulation Lock system geometry at start of a simulation option Checking this box ensures that the geometry of a system is locked in place in the System View window at the start of a simulation Enable geometry locking for new designs option Checking this box ensures that the geometry of newly created designs will be locked in the System View window by default Minimize curve windows at start of simulation option Checking this box causes all loaded output curve and output surface plot windows to be minimized at the start of a simulation Preserve array layout patterns between specs edits option Checking this box enables the preservation of defined array patterns even after the dimensions of the array are modified in its properties specifications dialog box See the section Patterning of arrays in this chapter for a discussion of Magsimus array patterning feature Always flag new designs for background job submission option Checking this box causes the
274. tes the currently selected anisotropy definition The user is prompted to confirm the deletion before it takes place Exchange Coupling tab E Array Specification 1 1 Flux concentrator Lines and Colors Calculation Control User defined Params Data Output Electromagnetic Geometry Magnetic Anisotropy Exchange Coupling Magnetoresistance Exchange param within array u erg cm Along u 1 Alona v 1 Along w 1 Coupling between components Exclude magnetization dependence Exchange param A u erg cm 0 3 V Apply cell to cell coordination in calculations Group Component 2 3 Free layer Define New Delete Fig 8 6d Exchange Coupling tab of Array specification dialog box The manner of the exchange coupling of the array the target being edited with the other components elements and arrays of the system is defined here Fig 8 6d An exchange coupling is characterized by a coupling field or an A parameter depending on the prevalent modeling environment that was specified by the user Use the main program menu selection Special gt Environment settings to modify the modeling environment A parameters are related to coupling fields and are expressed in units of micro erg per centimeter u erg cm or nano Joules per meter nJ m During calculations for each defined coupling the array experiences a field that has the same direction as the magneti zation of the coupled neighbor and a magnitude pro
275. than the barrier height In the software it is assumed that the voltage dependence saturates at the V U or V Ug behavior for larger applied voltages Bibliography Balabanian N and S Seshu Linear Network Analysis John Wiley amp Sons Inc 1963 Berger L Emission of spin waves by a magnetic multilayer traversed by a current Phys Rev B 54 9353 1996 Brown W F Magnetostatic Principles in Ferromagnetism North Holland Amsterdam 1962 Cheng D F Field and Waves Electromagnetics Addison Wesley Reading MA 1989 Daughton J M Magnetic tunneling applied to memory J Appl Phys vol 81 3758 1997 Hirota E Sakakima H and Inomata K Giant Magneto Resistance Devices Springer 2002 Hunt R P A magnetoresistive readout transducer JEEE Trans Magn vol 7 150 1971 Mallinson J C On damped gyromagnetic precession IEEE Trans Magn vol 23 2003 1987 Oti J O A micromagnetic model of dual layer magnetic recording thin films IEEE Trans Magn vol 29 1265 1993 Oti J O Simulmag Version 1 0 Micromagnetic Simulation Software Users Manual December 1997 Free software source code and manual downloads from Internet URL Attp math nist gov oommf contrib simulmag Oti J O An efficient three dimensional numerical magnetic shield model J Appl Phys vol 91 10 8290 2002 Press W H B P Flannery S A Teukolsky and W T Vetterling
276. the planar projections of the cell magnetization vectors A cell is toggled between on and off states by repeatedly clicking on it with the mouse When a cell is turned off its outline is drawn in pink without a magnetization vector An illustration of the layout of the array plane relative to its local coordinate frame is drawn in the upper right hand corner of the window Turned off cells do not appear in the diagram of the array in the System Display pane Fig 8 10b Several cells spanning a rectangular region can be turned on or off by selecting them en mass as follows Click and hold down the left mouse button on a cell at one corner of the rectangular region Without releasing the mouse button drag the mouse to the other corner of the rectangular region a rubber band box is displayed as the mouse is dragged Upon releasing the mouse the states of the cells linked by the rectangular region are switched Plane options Selecting any of the options u v v w or u w causes the projection of the array magnetization on the corresponding plane to be plotted The labels for the planes follow a horizontal vertical convention For example the label u v means that u is the horizontal axis pointing to the right and that v is the vertical axis pointing downwards Layer The cell layer parallel to the selected plane is specified here either by entering a value in the box or by moving the slider to a new position Reset pattern ar
277. the saturation magnetization of the shield The computation of the spatial fields produced by the surface poles is discussed below see the section Magnetostatic interaction field Magsimus provides dialog boxes for specifying the properties of shield components see the section Magnetic Shield Specification dialog of Chapter 6 and displaying maps of their surface pole distributions see the section Surface Charge Maps of Magnetic Shields of Chapter 6 Selected bounding faces of a shield component may be disabled by the user Furthermore the user is able to decide whether a shield component will interact with all magnetic components of the system or with a select few Note The total field H may or may not include the self fields of the shields that are produced by their own pole distributions The dialog box used to specify the properties of a magnetic shield gives the user the option of including or not including the self field contribution in H Effective fields The total field that acts on an element or array cell is the sum of the externally applied field and effective fields due to the magnetic interac tions in the system The manner in which the magnetic state of the element is modified by the applied field depends on the elements type Magsimus provides for applying external fields independently to the system as a whole and locally to its groups Complicated external field variations can be created by chaining simpler field defini
278. their input configurations are described below Note The discussions are carried out for the input configurations for static calculations but they are equally applicable to dynamic calculations with slight modification of the input labels Single external field definition dialog Field Oe o Polar angle Deg fo Azimuth angle Dea fo Fig 7 13 Single external field definition dialog This dialog allows the specification of a Single external field leg A Single field is one that is applied all at once to the design The field direction is given by the angular coordinates Polar angle and Azimuth angle The field magnitude is given by the Field entry Loop external field definition dialog Min field De 100 Max field De 100 Polar angle Deg 9U Azimuth angle Deg 0 No of data points 100 D o o Fig 7 14 Loop external field definition dialog This dialog allows the specification of a Loop external field leg The dialog is shown as it appears during the specification of a static simulation The labeling changes slightly when dynamic or quasi static simulations are being specified A Loop field is a closed field excursion applied to the design in a fixed direction of space The direction of the Loop field is given by the angular coordinates Polar angle and Azimuth angle The magnitude of a Loop field varies between two limits given by Min field the minimum field and Max field the maximum
279. thods and parameters specified by the user Group A description of the composition of a group A description of the location and orientation of the group coordinate frame in the system coordinate frame e An indication of whether a group electrical circuit is defined or not A description of the mechanical motions defined for the group Component the specific information that is generated depends on the component type Magnetic and electrical information of the component such as magnetization conductivity demagnetization factor values etc A description of the geometric properties of the component This includes the location and orientation of the component s local coordinate frame and its linear dimensions Magnetoresistive MR properties information Information on defined magnetic anisotropies Information on exchange coupling between components of the group and other components in the system The latest values of the vector components of applied external and internal fields acting on the component IEN Report for component 3 1 B x Magnetocrystallne anisotropies are not defined Exchange coupling information Exchange couplings are not defined Latest computed fields acting on component Oe For an array component such as this one the indicated fields are obtained by averaging among array cells External field System wide 0 0 300 Group wide 0 0 0 Total 0 0 300
280. tions The total effective field H acting on an element consists of the following compo nents The externally applied field H the magnetic anisotropy field H the magnetostatic interaction field Hj the exchange interaction field H the thermal fluctuation field H and the field H due to currents flowing in other elements of the system H H H H H H H 9 With the exception of H and H the calculation of each of these field terms is described in this section The thermal fluctuation field is discussed under the topic Thermal modeling below Magnetostatic interaction field The magnetostatic interaction field is a long range interaction field of a dipolar nature produced by the magnetic state of the system Uncompen sated magnetic poles are formed on the bounding faces of elements and array cells due to their uniform magnetization These together with the induced surface poles of shield components see above are the sources of magnetostatic fields in the system The magnetostatic fields show strong dependence on the geometric properties and mutual locations of the source components it produces a shape anisotropy in individual elements and arrays The field acting within a cell due to its surface poles is called its se f demagnetization field The geometric dependence of the field formulations are given by the gradients of appropriate scalar Green s functions This can be expressed in closed form for a uniformly magn
281. tions and initial and final magnitudes over a number of steps given by the No of data points entry The steps are equal for static and quasi static simulations but may vary for a dynamic simulation The entries Total field duration Ang Velocity angular velocity are relevant for dynamic quasi static calculations only They represent respectively the duration of the rotation field and the rate of change of the field direction during transient non equilibrium processes of the simulation Pulse external field definition dialog Base field Oe 130 Field amplitude Oe 40 Rise steps 10 Fall steps 5 Duration steps 3 Polar angle Deg 30 Azimuth angle Deg 1180 Fig 7 16 Pulse external field definition dialog This dialog allows the specification of a Pulse external field leg The dialog is shown as it appears during the specification of a static simulation The labeling changes slightly when dynamic or quasi static simulations are being specified A pulse field is a field of limited duration that is switched between two magnitudes in a fixed direction of space The field magnitudes are given by the Base field and Field amplitude entries The field magnitude is initialized to the base value It is incremented or decremented as the case may be to the field amplitude value over a number of steps given by the entry Rise steps For dynamic and quasi static simulations time duration is implied and the dialog displays Rise ti
282. titled to any refund if this agreement is termi nated Upon termination Licensee shall return all copies of the SOFTWARE and DOCUMENTATION Limited Warranty limitation of remedies For a period of thirty 30 days from delivery MagOasis warrants that each SOFWARE will conform in all material respects to the description of such SOFWARE s operation in the DOCUMENTATION In the event that the SOFWARE does not materially operate as warranted Licensee s exclusive remedy and MagOasis s sole liability under this warranty shall be 1 the correction or work around by MagOasis of major defects within a reasonable time of not more than 90 days from discovery or 2 should such correction or work around prove neither satisfactory or practical termination of license and a pro rated refund of the license fee paid to MagOasis for the SOFWARE component If the software license is of indefinite duration permanent license then the assumed duration of license for the purposes of computing a pro rated refund shall be 6 months THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE MAGOASIS SHALL NOT BE LIABLE FOR ANY SPECIAL INCIDENTAL OR CONSE QUENTIAL DAMAGES INCLUDING WITHOUT LIMITATION LOST PROFITS Licensee accepts responsibility for its use of the SOFWARE and the results obtained therefrom Limitation of Liability MAGO
283. tization Mx Y component of magnetization My Z component of magnetization Mz Magnetization along external field Mh Magnetization magnitude M Magnetization X component of external field HextX Y component of external field HextY External field Z component of external field HextZ External field magnitude Hext System external field amplitude HextA Anisotropy energy density Wani Exchange energy density Wexc External field energy density Wext self demagnetization energy density Wdm Energies Anisotropic magnetoresistance AMR Magnateresistandb Giant magnetoresistance GMR 96 Table 1 2 Data output Categories for elements These apply to arrays for which outputs averaged over the array are generated Data Category Data type Distance General Iterations Time u component of magnetization Mu v component of magnetization Mv w component of magnetization Mw Magnetization along external field Mh Magnetization Magnetization magnitude M u component of magnetic induction Bu v component of magnetic induction Bv w component of magnetic induction Bw Magnetic induction along external field Bh u component of external field HextU v component of external field HextV w component of external field HextW External field magnitude Hext System external field amplitude HextA External field energy density Wext External field u component of anisotropy field HaniU v c
284. tput of 89 Anisotropic Magnetoresistive AMR Ratio box in Magnetoresistance tab of Array specification dialog 189 Anisotropic option Relative permeability in Electromagnetic tab of Array specification dialog 184 anisotropy 7 69 anisotropy field 80 185 A parameter exchange specification parameter 186 Apply botton in Moving Component dialog box 160 Apply cell to cell coordination in calculations inter element coupling in Exchange Coupling tab of Array specification dialog 187 Apply this total time bound in Calculation tab dialog of System specification dialog 165 array 227 Array matrix dimensions frame 32 in Geometric tab of Array specification dialog 181 Array outline Current density vector arrow and Magnetic vector arrow options in Lines and Colors tab of Array specification dialog 191 Array specification dialog box 31 Arrays 108 Auto axis attribute in Plot settings dialog box 212 auto playback mode 230 Automatically scale new output curves in General Option tab dialog of Environmental Settings dialog 115 auto repeat playback mode 230 Axes attributes frame in Plot settings dialog box 212 Azimuth angle box 42 47 in Loop external field definition dialog box 155 in Rotating Component dialog box 149 in Single external field definition dialog box 154 Azimuth angle range area in Rotation external field definition dialog box 156 Azimuth box 33 39 40 46 in External Field Controls 138 Azimuthal orien
285. trical current signals below The input areas for these characteristics are displayed on the left side of this tab of the dialog box Stimuli to edit area The stimuli to edit is specified by selecting an option here Thermal or MMF Actions area Compute stimulus for component Checking this box causes Magsimus to apply the stimulus selected in the Stimuli to edit area during simulations Temp Leg or MMF Leg Drop down list of the leg numbers Selecting a item here causes the data input area of the leg to appear on the data input area Temp Type or MMF Type Drop down list for selecting the stimuli type Add Adds a new stimuli leg Delete Deletes a stimuli The user is prompted to confirm the deletion before proceeding Clone Creates a duplicate copy of the selected leg Clear A11 Deletes all legs The user is prompted to confirm the deletion before proceeding Preview signal Pressing this button displays a window that shows a plot preview of the defined signal leg that is currently being edited E Array Specification 1 1 New Ele Electromagnetic Geometry a Magnetic Anisotropy Exchange Coupling Magnetoresistance Stimuli sources Lines and Colors Calculation Control if User defined Params Data Output r Stimuli to edit Thermal C MMF Signal pattem 101 Max Temperature K fi Actions Min Temperature K o i P Signal leg fi op No rise time ste
286. ts Design example 17 Inter cell exchange coupling 228 intra layer exchange coupling 62 Iteration 82 Iteration Control area in Calculation tab dialog of System specification dialog 164 I Type list 37 job control actions 127 K Kilonewton kN 117 L Landau Lifschitz 164 Landau Lifschitz equation 71 192 228 Landau Lifschitz Gilbert 164 Landau Lifschitz Gilbert equation 71 192 228 Launch all computed curves System display pane action menu 146 Layer box in 2 D vector window 218 in array patterning dialog box 205 Layer reset button in array patterning dialog box 205 left view of design 148 Length list in Start up Units tab dialog of Environmental Settings dialog 116 Length Lu box 23 25 31 33 array size in Geometric tab of Array specification dialog 181 array size in Geometric tab of Magnetic Shield specification dialog 199 license 242 License access type Magsimus About dialog box 107 License expiration date Magsimus About dialog box 108 License Grant 243 246 license instances 13 License type Magsimus About dialog box 107 Licensee 107 242 245 Limitation of Liability 244 limitation of remedies 244 Limited Warranty 244 Limiting outline array outline type 142 Line thickness in Color attributes tab dialog of Environment Settings dialog 119 in General tab dialog of System specification dialog 163 Line thickness frame in Plot settings dialog box 213 Line thickness list in Lines and Colors tab of Array s
287. ty Wexc Table 1 3 Data output Categories for a probe Data Category Data Type X component magnetostatic interaction field HmstX Y component magnetostatic interaction field HmstY Z component magnetostatic interaction field HmstZ Magnetostic interaction field magnitude Hmst Magnetostatic interaction energy density Wmst X component self demagnetizing field HdmX Magnetostatic Y component self demagnetizing field HdmY Z component self demagnetizing field HdmZ self demagnetization field magnitude Hdm self demagnetization energy density Wdm X component field from shield sources HShldX Y component field from shield sources HShldY Z component field from shield sources HShldZ x component total field HtotX y component total field HtotY Sonal elds z component total field HtotZ Total field magnitude Htot Current Voltage V Electrical Conductivity Cond X component electrical current field HleX Y component electrical current field HleY Z component electrical current field HleZ X component magnetic force FX Magnetic force Y component magnetic force FY Z component magnetic force FZ Table 1 4 Data output categories for a magnetic shield Data Category Data Type Distance General Iterations Time Current Electrical Voltage V Conductivity Cond u component magnetic force FU v component magnetic force FV w component magnetic force FW X component magneti
288. us is submiting jobs to run in the background Updating tables Certain tables required for carrying out a simulation are currently being updated Writing check point please wait A check point backup file is being updated Saving to file Please wait A design is being saved to file Environment Settings dialog box The Environment settings dialog box Fig 6 7 provides the means for the user to tailor the Magsimus software environment to appear and operate in a manner that meets his or her specific needs or tastes This dialog is displayed by selecting the entry Special gt Environment settings in the main program window Pressing the buttons named Set to defaults in the tab windows sets the specifications to their default values General Options tab Start up Units I Color attributes I Calculation control Replay available recordings upon design load Enable recording to external disk files for new designs oo es Show tip of the day at start up Design projection attributes v Enable simulation check pointing for new designs Projection method Cabinet J Enable end of simulation geometric reset for new designs Projection angle Deg 30 JV Lock system geometry at start of a simulation r Always express exchange using Field Enable geometry locking for new designs Enable simulation auto continue feature for new design Minimize curve windows
289. uses the carousel to be played back once Checking the Randomize playback sequence box causes the carousel to play back files in a random sequence You can add and remove files to an existing carousel skip one file ahead or backward by using the relevant buttons of the carousel window You assign a name to a new carousel you create when you save it The playback of a carousel is paused whenever a design not containing a recorded simulation is loaded into the program Pressing again the Pause button now having the caption Continue resumes the playback of the carousel Refer to Chapter 7 System views for additional information on the recording playback carousel FEIBEEHFTEELESERS oo Eig System view Writing dots e B Recording Playback Carousel PaternedediaLxample cr x L FO Wilting dots l E Paltemed media iler External Field Controls TF Use field definitions Ed i dn D FA 2 1 Write current profile DoR Simulation Statie Recording playback is paused Computed time ns 0 11 708059 n O Fig 3 17 Snapshot of the playback of the sample patterned media carousel described in the text Magsimus productivity tools Magsimus provides a variety of very powerful tools designed to make your modeling tasks more efficient and productive The context sensitive online help feature the parametric simulation capa
290. utput dialog above 2 D plot windows are generated for non parametric simulations or parametric simulations for which Generate parametric data check box has not been selected in the External field and system simulation specification dialog Parametric output windows are generated if the Generate parametric data flag is selected Additionally a 2 D vector plot window that is continually updated can be displayed for an array component These plot windows are described next 2 D Plot window A 2 D plot window is shown in Fig 8 12 The window s caption conveys both information about the component it belongs to and the type of output plotted The general format for the caption is lt component desig nation gt lt output description gt The component designation for a group is n where n is the position of the group in the system The component designation for an element array or probe is of the form n m where n is the designation for the parent group of the component and m is the position of the component in the group The caption 1 2 Current I mA Vs Iterations in Fig 8 12 refers to plotted electrical current as a function of calculation iterations for the second component of the first group of the system the caption for the second data definition shown in Fig 8 11 if the group were the second in the system would read 2 External field energy density Wext erg cc Vs Distance traveled EN 172 Current
291. uttons at the top and below this the System Structure list The System structure list displays the system hierarchy At the top of this hierarchy is the system which consists of groups at the second level of the hierarchy The groups in turn consist of basic components which are at the lowest level esas uro Fig 3 3 Start up screen of Magsimus The numbered regions are 1 tool bars of main program window 2 Design Manager 3 External field controls 4 System display panel of the hierarchy The entries in the list are appropriately indented to reflect this hierarchy A system object entitled New problem in Fig 3 3 containing an empty group entitled New Groupl is created whenever the program is started or whenever the creation of a new design is started by selecting the menu item File gt New problem in the main program menu An identifying icon accompanies each entry in the list To select an item on the list click on it s icon once to highlight it s entry New groups and other components can be added to the design by clicking an appropriate action button A new group is appended to the bottom of the list at the group level New basic components of a selected group are appended to the bottom of its sub list in the System Structure list Another way of adding new groups and components is by right clicking the mouse in the System Structure list and making appropriate
292. value in GMR formulas If this box is checked equation 22 of Chapter 5 is used otherwise equation 21 is used Allow MR to modify array conductivity option Checking this box enables the modification of the intrinsic conductivity of the array by MR effects during calculations Anisotropic Magnetoresistive AMR Ratio AMR ratio of the array commonly referred to as AR R Refer to Chapter 5 Mathematical Theory for a discussion of AMR Giant Magnetoresistance GMR coupling area Enable spin momentum transfer SMT effects with cou pled components Checking this box causes spin momentum transfer SMT effects to be considered in the computation of the magnetoresistive response of the component The model for SMT which involves the interaction between polarized electrical currents and the magnetization of components is discussed in Chapter 5 Use SMT classic model Checking this box indicates the use of the classic Slonczewski SMT model for the component being edited SMT field per current SMT field per current This isa field pre factor that is relevant in the alternate SMT model for dynamic and quasi static calculations that is when the box Use SMT classic model is un checked This pre factor also used in formal extension of SMT response to static calculations see Chapter 5 Couple new component Pressing this button displays a dialog that allows the specification of a new element or array to GMR couple to Probe ele
293. ver available recorded data is about to be over written Miscellaneous vector Colors and Lines area The line colors and widths used in displaying the pinning field vector the mag netic anisotropy vector and electrical circuit lines the loaded system are speci fied here Modification of the displayed attributes apply to the currently selected option Color Pressing this button displays a dialog box for editing the line color The currently selected color is displayed at the swatch to the left of this button Line thickness The line thickness is specified here either by typing in a value in this space or by selecting a value from the drop down list A sample of the defined line is displayed at the swatch next to the left of the input field Calculation tab This dialog is used for the selection and management of the calculation method and for exerting some control over the manner of displaying successive system state frames diagrams in the System Display window during calculations Fig 8 1b An equilibrium state of the system corresponds to a local free energy minimum of the system The energy minimum is also equivalent to the vanishing of the torque per unit volume acting on every component of the system The system goes through several non equilibrium transient states in evolving from one equilibrium state to another Calculations are carried out with solvers that use iterative methods in solving the defining system equations of the
294. ystem can thus be accom plished by first designing and optimizing smaller sub designs and then importing and assembling them into a final larger design The groups of an imported system are appended to those of the loaded system The window for importing components is shown in Fig 8 21 This window is displayed by pressing the Import components icon in the Design Manager Importing components Drive File Type C Magsimus Files mus M Show Magnetization vectors Directories Files Show Electrical circuits Show Mag Anisotropy axes Show Coordinate Axes System views System structure patterned media i MR readback sensor Patterned media Import Cancel Help Fig 8 21 Component importation window Drive Lists and allows the selection of drives connected to the computer Directories Lists the file directories Files Lists the files of the selected file directory File type Lists file filters System structure Displays the system hierarchy of the design selected in the Files list Selecting the system entry the root in the hierarchy displays the whole system in the System views area described below selecting a group displays the group and its compo nents selecting a component displays only that component System views The diagram of the system contained in the file selected in the Files list is displayed here The different views of the system fro
295. ystem display pane of System View Window 138 system display pane 131 System level option in Select field scope frame 41 System level option in system external field specification dialog 150 System structure box in integrated Design Manager 134 T T uu tensor value Relative permeability in Electromagnetic tab of Array specification dialog 184 T vv tensor value Relative permeability in Electromagnetic tab of Array specification dialog 184 T ww tensor value Relative permeability in Electromagnetic tab of Array specification dialog 184 Target box 48 Target list in Parametric simulation tab 153 temperature 194 Temperature coeff in Electromagnetic tab of Array specification dialog 183 in Magnetic Anisotropy tab of Array specification dialog 185 temperature coefficient 183 185 temperature coefficient of field 93 Teukolsky 97 Teukolsky S A 97 Thermal modeling 92 thermal sources 194 thermal fluctuation field 75 Thickness Lw box 23 25 32 33 array size in Geometric tab of Array specification dialog 181 array size in Geometric tab of Magnetic Shield specification dialog 199 Tight outline array outline type 142 time 71 82 Time list in Start up Units tab dialog of Environmental Settings dialog 116 Time step per iteration box in Calculation tab dialog of System specification dialog 165 time dependent 70 Tip of the day window 114 121 toggle device switching modes 151 top view of design 148 torque 163 tot
296. zing a vector field distribution in a region of space Like material arrays they are characterized by cells and field points coincide with centers of cells A probe is a design primitive used primarily to sense the value of a design output at a point in space A magnetic shield represents an ideal linear soft magnet it interacts with other components of the system by means of free poles that are induced on its surface A view of the system design manager illustrating the system hierarchy for a system called System example is shown in Fig 4 1 gt Sie P Oo CP Ex Le stem example J New Group Normal magnet Pseudo soft magnet Permanent magnet Hon magnet LJ Probe Magnetic shield Aray of normal magnetic shields New Element Fig 4 1 System design manager dialog Elements and arrays may be magnetic or nonmagnetic electrically conducting or non conducting and have a range of material properties These properties are described in the section Review of component properties below Fig 4 2 shows an array element and probe on display in the software Output data is calculated for groups and for components making up a group The classification of elements into groups facilitates the design of systems composed of functionally separate devices Groups can vary widely in complexity from the simplest group containing a single component to one composed of many components of different types and material properties and different shapes

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