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Vibrating Sample Magnetometer - Materials Research Facilities

1. eese 5 10 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Figure 6 1 Figure 6 2 Figure 6 3 Figure 6 4 Figure 6 5 Figure 6 6 Figure 6 7 Figure 6 8 Figure 6 9 Figure 6 10 Figure 6 11 Figure 6 12 Figure 6 13 Figure 6 14 Figure 6 15 Figure 6 16 Figure 6 17 Figure 6 18 Figure 6 19 Figure 6 20 Figure 6 21 Figure 6 22 Figure 6 23 Figure 6 24 Figure 6 25 Figure 6 26 Figure 6 27 Figure 6 28 Figure 6 29 Figure 6 30 Figure 6 31 Figure 6 32 Figure 6 33 Figure 6 34 Quantum Design Contents Table of Figures Using the MultiVu dropdown Utilities menu and Option Manager to activate the bAJUM IEEE 6 2 The MultiVu window and the VSM Control Center VSM SIM including the Install tab the VSM Status area and the MultiVu Status bar 6 2 The MultiVu window and the View dropdown menu showing VSM immediate mode comminds dedere Perret e Pe e ceterae rite ere utr aed 6 3 The MultiVu window and the Sample dropdown menu showing VSM immediate mode commands 52 rn ete et epe ee t be eon to eei te et 6 3 The Specify Sample Location dialog that opens from the dropdown menu when you select Sample gt gt VSM Manual Locate eeeeeeeeeeeeeeeeeene eene 6 4 VSM immediate mode commands in the context of the MultiVu window and the Measure dropdown menu 3 tee eden ite tee te epe tae tee
2. PSync Ground Sync Data Clock Of olnNnyi ono aye ow N PSync Quantum Design VSM Option User s Manual 1096 100 Rev BO A 5 February 2011 Section A 3 Appendix A 2BModel CM A VSM Motor Module Front Panel Model CM A VSM Motor Module A 3 2 4 JA 4 AUX CONNECTOR This connector provides three analog inputs and three digital I O lines for future options OOOOO OOOO MALE Figure A 5 JA 4 Aux connector for the Model CM A VSM motor module Table A 5 JA 4 Aux connector for the Model CM A VSM motor module PIN FUNCTION 45V Digital I O P3 10 n c Analog Input P5 13 Ground Digital O P3 11 Digital l O P3 8 Analog Input P5 12 oioj iojo j n ijico nm Analog Input P5 14 A 3 2 5 JA 5 MONITOR BNC This connector is for use by Quantum Design It can be configured to output signals for diagnostic purposes By default the firmware is configured to output the motor position here A 6 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix A Section A 4 Model CM A VSM Motor Module Model CM A VSM Motor Module Rear Panel A 4 Model CM A VSM Motor Module Rear Panel The rear panel of the module contains an address selector a single guide hole and the CAN connector through which the module sends and r
3. esses en rennen 6 5 6 4 1 T Install Tab eee nete ee e P e ee e Stele 6 5 6 4 L 2 Data File Tab oed eene andate angebote 6 6 6 4 1 3 Sample Tab tee e Lye eere e eee e Usu ee eR LEE UE ise 6 7 6414 Advanced Tab uuo nee eese ee Pedes t it cet E ree Reed 6 7 6 4 VSM Control Center Measure Button esee enne nennen nennen 6 8 6 4 2 1 VSM Measurement Dialog Buttons 6 8 6 4 2 2 VSM Measurement Dialog Last Measurement essere 6 8 6 4 2 3 VSM Measurement Dialog Settings Tab ssessseeeeenee 6 8 6 4 2 4 VSM Measurement Dialog Centering Tab see 6 9 6 4 2 5 VSM Measurement Dialog Advanced Tab eee 6 9 6 5 Overview of Sequence Mode VSM Commands sees neret 6 11 6 6 Sequence Mode VSM Adv Measure Command eese nennen 6 12 6 7 Sequence Mode VSM Center Sample Command essere 6 12 6 8 Sequence Mode VSM Moment vs Field Command eee 6 12 6 8 1 Sequence Mode VSM Moment Versus Field Dialog eene 6 13 6 8 2 Sequence Mode VSM Moment versus Field Dialog Setup Tab 6 13 6 8 2 1 Field Sequence Settings eese ener nennt 6 14 6 8 2 2 Field Control Settings 5er ERES Te sees pars Ine ERE aaas 6 14 6 8 2 3 Data Acquisition Settings sesssssssseseseeseeeee ee
4. Power Return 24V Sync Low Line Sync System Ground CAN High Sync High Reset 24 V DC Of olny ono ayR ow N Maintenance Service Note 1096 307 The CAN motor module CM A QD part number 4101 100 which is used to drive the linear motor of the VSM option dissipates a significant amount of heat when providing the large currents sometimes over amp to the motor drive coil Therefore it is critical that adequate air cooling is supplied by the fan on the back of the Model 1000 Modular Control Center If the motor module overheats the current output is turned off abruptly until the amplifiers cool sufficiently at which point the current is turned back on This causes erratic behavior of the motor and presents a hazard to the user It might also result in damage to the hardware or your research sample VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix A Section A 5 Model CM A VSM Motor Module Maintenance To help prevent such overheating effects please follow these guidelines WARNING As with any CAN module turn off the power to the Model 1000 before inserting or removing the motor module Regularly every few months clean the filter of the air intake fans on the back of the Model 1000 In the case of the upper fan for the module cooling this is the most critical fan remove the filter by first pu
5. 5000 max at Intervals Sticky Autorange o Ho Delta Time fo sin C Always Autorange 5000 Hmin time C Fixed Range De Click and drag to choose start and end fields Delta Field fo Oe Field Control Approximate Fields 7 Ben fo K Sweep Rate fi 0 Oe sec ERES PPMS Data Logging n at each isl No Automatic Centering Select Persistent at each field Sweep Advanced Settings End Mode Persistent v Require Sweep Mode For Continuous Acquisition r Data Acquistin Wait Time At o sec Uniform Spacing in Log Field Each Step Restore Averaging Time 1 sec Approach Mode Linear Defaults 2 Number ot Fjelde 25 M Excitation Parameters M S Fadlan E De Peak Amplitude P mm Frequency jao ba Hz Repetitions at 1 Estimated each Field Time 00 42 hm Maximum Acceleration fi 26 331 m sec Keep all measurements Lines 61 Maximum Moment f 0 46875 emu ox e 5 x jum Figure 6 20 Advanced tab of the sequence mode Sequence Mode VSM Moment versus Field Dialog Setup Tab The Setup tab Figure 6 19 organizes the parameters relevant to a field sweep or hysteresis measurement Options in the Field Sequence Field Control and Data Acquisition subsections of the tab allow you to control the settings A scroll bar at the right side automatically displays Approximate Fields The subsections and their settings are explained b
6. c ge J c 3 it 0s J pm m d tnaa Vibrating Sample Magnetometer VSM Option User s Manual Part Number 1096 100 BO Quantum Design 6325 Lusk Boulevard San Diego CA 92121 USA Technical support 858 481 4400 800 289 6996 Fax 858 481 7410 Fifth edition of manual completed February 2011 Trademarks All product and company names appearing in this manual are trademarks or registered trademarks of their respective holders USS Patents 5 053 834 High Symmetry DC Squid System 5 139 192 Superconducting Bonds for Thin Film Devices 5 311 125 Magnetic Property Characterization System Employing a Single Sensing Coil Arrangement to Measure AC Susceptibility and DC Moment of a Sample patent licensed from Lakeshore 5 319 307 Geometrically and Electrically Balanced DC Squid System Having a Pair of Intersecting Slits 5 647 228 Apparatus and Method for Regulating Temperature in Cryogenic Test Chamber Foreign Patents U K 9713380 5 Apparatus and Method for Regulating Temperature in Cryogenic Test Chamber Canada 2 089 181 High Symmetry DC Squid System Japan 2 533 428 High Symmetry DC Squid System Japan 2 533 428 High Symmetry DC Squid System Safety Instructions are inside Refer servicing to hazard replace fuses only with same type qualified personnel and rating of fuses for selected line voltage j No operator serviceable parts For continued protection against fire Observe the followi
7. 1 sec Logging Interval f 0 site o Field represents the average field in oersted o Moment represents the average of the moment over the averaging time in emu o Moment Std Error represents the error on the L Stt Pase Coe ne mean that is the error bar on the reported moment Figure 6 14 VSM Measurement dialog and the Settings tab 6 4 2 3 VSM MEASUREMENT DIALOG SETTINGS TAB The Settings tab Figure 6 14 is divided into options for Measure Type and Measurement Parameters Measure Type Measurements can be taken in Continuous mode in which new data is collected and written to the data file until the Stop button is pressed The Single Measurement mode collects one data point upon pressing the Start button Measurement Parameters o Averaging Time specifies the boxcar average duration for each measurement and will be an integer number of periods of sample oscillation A practical minimum for this time interval is 0 5 seconds and a typical value is 1 second o Logging Interval is the amount of time that elapses between recorded measurements in seconds If you set Logging Interval to a value less than Averaging Time then one data 6 8 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 Section 6 4 VSM Software VSM Control Center 6 4 2 4 VSM MEASUREMENT DIALOG CENTERING TAB The Centering tab Figure 6 15 displays the automatic centering settings
8. 2 2 3 Install the Coilset Puck The coilset puck contains the VSM detection coils and a thermometer for monitoring the sample temperature You will insert the coilset puck into the sample chamber by using the standard puck insertion tool and the same procedures that are used to insert other types of pucks see the system User Manual for more information Install the puck before you insert the sample tube 1 On the system verify that all items have been removed from the sample chamber opening including the standard centering ring 2 Locate the serial number of the detection coilset puck 4096 204 or 4096 600 as shown in Figure 2 2 This serial number will be used to identify the calibration data for the coilset in a later step 3 Insert the coilset into the sample chamber by using the puck insertion tool as illustrated in Figure 2 3 The puck insertion tool is also referred to as the puck extraction tool the sample holder tool and the sample insertion sample extraction tool depending on context 2 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 2 Section 2 2 Installing and Removing the VSM Option 1BInitial Installation of the Hardware and Software MOUNTING RING FOR PUCK INSERTION TOOL ce EXTRACTOR eL sev Qo 0 OQ COILSET SERIAL NUMBER bewar O E REQUIRED BY SOFTWARE es em LA Figure 2 2 Coilset puck 4096 204 or 4096
9. enne nnen A E tentent tnnt nnennss A 2 A 2 2 SDeCITICatlODS c iiti cnt rt ace te pe Ate le iet bett a e e E ae e Ceo ete taneesaotey A 3 A 3 Model CM A VSM Motor Module Front Panel essere A 3 AO T Indicator LEDS oce RE qe OR D POR aa Da SEDE e tees A 3 A 3 2 Connectors and Pinout Tables esssssssssssseseseeeee eene nennen ennt entente A 4 A 3 2 1 JA T Servo Gonnectot 4 een iom ree reete eere eee dere toi REP e A 4 A 3 2 2 JA 2 Stepper Connector ee repete Halts eh na A 5 A 3 2 3 JA 3 Motor Sync Connector eese etienne oon tton setae ipea A 5 A 3 2 4 JA 4 Aux Connector onneen r ER ee eene enne tenen th seen E entes enne A 6 A32 A25 Monitor BNG iin et D ERE EGERIT T WSESERR aesa aai A 6 A 4 Model CM A VSM Motor Module Rear Panel eese enne A 7 A41 Address Selector tore rete oe eee eee ee aede eto e Pret eee bee e erue e Eae ee A 7 A42 Single Guide Ole s vere nett Er ert ntes e eto Peer eru e ades A 7 A 4 3 OD CAN Connector o cheat PA Le aoe ee AR ied Ce e a RE TER eee de A 8 A5 Mamtehnance u e e Ea lotsa sides SERERE RENI EO SOTRA uaa dase A 8 APPENDIX B Model CM B VSM Detection Module rece eee eee eee ee eene en ena n eta setas t ese tn sense tuae B 1 Bel Introduction io RE dete et aee Hin ree E PR Eee rH e eise B 1 B 2 Functional OVervie W x dete eere tient p tete duc sane Ie de Eg Pee te ete aee ve eee cede ve e EE eg
10. BO Quantum Design February 2011 Chapter 6 VSM Software 6 5 Section 6 5 Overview of Sequence Mode VSM Commands Ranging The Ranging setting refers to the way the system chooses the gain of the amplifiers in the VSM module during a measurement the optimal setting is typically Sticky Autorange The preamplifiers in the VSM module can change the gain ranges by factors of 10 depending on the size of the signal that is induced in the pickup coils In the rare case when you need more control than is offered by Sticky Autorange you can change the Ranging setting o Sticky Autorange recommended The system automatically increases the gain by a factor of 10 if the current peak signal drops below 2 of the current range The system automatically decreases the gain by a factor of 10 if the current peak signal exceeds 50 of the current range o Always Autorange The system automatically increases the gain by a factor of 10 if the current peak signal drops below 9 of the current range The system automatically decreases the gain by a factor of 10 if the current peak signal exceeds 100 In some cases the Always Autorange setting might improve the signal to noise ratio However this setting could also lead to an increase in the number of range changes and a corresponding drop in data throughput o Fixed Range The system always uses the specified gain range This can be useful when measuring samples which change signal rapidly e g fer
11. 2 APPNAME NFO 0 MOMENT UNITS NFO Titanium oxide SAMPLE MATERIAL NFO stock sample 1 SAMPLE COMMENT NFO 001 SAMPLE MASS NFO SAMPLE VOLUME NFO SAMPLE MOLECULAR WEIGHT NFO SAMPLE SIZE NFO irregular SAMPLE SHAPE NFO 34 95 SAMPLE OFFSET DATATYPE COMMENT 1 DATATYPE TIME 2 STARTUPAXIS X2 STARTUPAXIS Y1 5 Data Comment Time Stamp sec Temperature K Magnetic Field 0e Moment ull IZ Figure 6 34 A Raw Data view of a VSM data file 6 10 2 Fields in VSM Data Files Table 6 1 defines the fields in a VSM data file and Section 6 4 1 3 explains how to create VSM measurement data files Table 6 1 Definitions of column headers for VSM data files dat files shown in the order they appear COLUMN HEADER TERM DEFINITION Comment user specified comment added by using the Datafile Comment command Time stamp sec time stamp Temperature K average temperature T of the sample during measurements The sample temperature is measured by the coil thermometer Magnetic field Oe average magnetic field during measurement Moment uu average magnetic moment of the sample during measurement uu user units emu or A m M std err uu standard error i e the error of the mean for the measurement Transport action 1 measurement 2 auto touchdown 3 manual touchdown Averaging time sec number of cy
12. 2 2 8 Configure the VSM Systetn 4 eite detecte tcd Rete a Re eaae de 2 10 2 3 Removing the VSM Option osa oe ees e XR E HIER eee ber ne A eas 2 12 2 3 Prepare Tor Removal ree etre tei eite tto 2 12 2 3 2 Deactivate th VSM OptOnD ict e eite a e bed ee EHE Fee dedu e Ra ela de 2 13 Quantum Design VSM Option User s Manual 1096 100 Rev BO V February 2011 Contents Table of Contents 2 3 3 Remove the VSM Linear Motor Transport nennen 2 13 2 3 4 Remove the VSM Sample Tube and Coilset Puck eene 2 13 CHAPTER 3 Sample Preparation and Mounting cccscccssscsssssccssssccsssscssseccsssscsssssssssssscssssscssssscoess 3 1 Slt Introduction ote tete pete eee e attese tied aces altel en Mea Li a doceat adeo 3 1 3 2 Sample Properties iirc c Ere ATA EG ee etre dete titer tte fe e eet ere 3 1 3 2 1 Size and Shape uet e e c e iip ker i e eee eke 3 1 3 2 2 Errors from Radial Offset of Sample esses eene nennen 3 2 3 2 3 S1ize of Magnetic Moment enne emi ener qe ee THERE det tete iced ue 3 3 3 3 Mounting Samples aen treteet pne ete entree iti aote PU e e Eque rte dee TROP sie 3 3 3 3 1 Accurate Sample Location i epe sal ett biete ober ses EE RE Lee eene gcn 3 3 3 3 2 VSM Sample Mounting Techniques Application Note 1096 306 3 4 CHAPTER 4 EC Suri iwancicee e 4 1 AN Introd ction sere rete ee
13. 4 mm you also ensure that the sample holder clears the puck surface For example taking into account that the detection coils are 40 mm above the puck surface and using a sample offset of 35 mm the use of a Peak Amplitude of 5 mm or greater would cause the sample holder to touch the puck surface which could dislodge the sample or the sample rod o The Frequency is typically 40 Hz it specifies the frequency with which the VSM oscillates the sample It can be moved to a different value if there is interference at 40 Hz See PPMS Service Note 1096 304 at www qdusa com for information about changing the vibration frequency o Max Accel is computed from Frequency 40 Hz and the Peak Amplitude entry it represents the maximum acceleration the sample will experience during a measurement in units of meter per second squared Important Do not proceed with a measurement if your sample cannot tolerate accelerations of this magnitude To reduce the acceleration reduce the amplitude o Max Moment is computed from Frequency 40 Hz and the Peak Amplitude entry it represents the maximum sample moment that can be measured using these settings Important Do not proceed with a measurement if the magnetic moment of your sample is larger than the calculated Max Moment as the system will not be able to complete the measurement Larger moments can be measured by using relatively small values for amplitude 6 10 VSM Option User s Manual 1096 100 Rev
14. 6 0 3 2 Rangin Settings inne ertet estet erue HH eSI IRE PI Dee needa 6 22 6 0 3 5 PPMS Data Logging Setting Sisirin entente ete ette teet te tatnen nnde 6 22 6 9 3 4 Advanced Set ngs ins cct tire Hn D ud ve deett eate 6 22 6 0 3 5 Excitation Parameters 252 eor ten tte lathe csetgin escola ertt scire inner 6 23 6 107 V SM Data Files uoc p eed pee oie ert ieee cies 6 23 6 10 1 Data Eile Headets eet e Eee PTT Er ree ro SERRE T HEUS 6 23 6 10 2 Fieldsin V SM Data File Shae 5 eerte anneni eenn tee Ph er ete ei Pb e ee PERRA Sede 6 24 CHAPTER 7 Troubleshooting 4253 vere capi vc erae piae CHORI EU seastenccadincacecateadecidiveds Oed a adag elo o orb M ARE RED DNA Ro Pee DK eR 7 1 Tl Introduction ze been teni erecta eer eee 7 1 7 2 OVOtVIEWz i pite te iE dde Ge tet st e n do e Sede tna ee e o ee Dose iE eus 7 1 Tor Mibration of the Detection Coll Set nocte nre eter pee dade bush trie ebd eene e eaS 7 2 7 4 Sample Centering and Temperature Dependent Magnetization Measurements 7 3 7 5 Mounting Samples Loosely Causes Moment Noise eese 7 1 7 6 Performing VSM Measurements in PPMS High Field 14T or Higher Magnets 7 8 APPENDIX A Model CM A VSM Motor Module 4 ce eeeeeeee ee ee eese seen sese ense seen sete eese tete s eee aooee A 1 Asl Introduction een eee ede Ped a Paid ale ise ges A 1 A 2 Functional OyervieW EE A 1 A 2 1 Functional Block Diagram
15. 6 4 2 3 has more information about Averaging Time Number of Temperatures and Temperature Increment When you select a uniform temperature spacing instead of Continuous Measuring you must define the spacing between the temperatures with the Number of Temperatures or Temperature Increment options Figure 6 31 o The Number of Temperatures value sets the number of temperature set points at which VSM data will be taken This number of temperature set points will be distributed uniformly over your defined temperature range in the manner you have selected If you select the Number of Temperatures radio button you must enter a number in the associated text box o The Temperature Increment value sets the temperature increment in degrees Kelvin between VSM measurements If you select the Temperature Increment radio button you must enter a number in the associated text box Note If you set a step size that does not fit evenly with your selected Start and End temperatures the program will adjust the increment size slightly to include the Start and End temperatures Repetitions at each Temperature The Repetitions at each Temperature value Figure 6 32 sets the number of data points the VSM will take at each of the temperatures shown in the Approx Temperatures list This value will have no effect if you have also selected the Sweep or Continuous Measuring modes Keep The Keep dropdown menu bar see Figure 6 32 is availabl
16. BO Quantum Design February 2011 Chapter 7 Section 7 6 Troubleshooting Performing VSM Measurements in PPMS High Field 14T or Higher Magnets significant magnetic noise emanating from the superconducting magnet at these fields and this is picked up by the VSM detection coilset which lies in the center of the magnet The noise originates from magnetic flux jumps in the windings of the high field superconductor insert which is composed of Nb3Sn wire Magnetic field penetrates a superconductor in the form of miniscule discrete flux lines The magnet windings immobilize or pin the magnetic flux lines and Nb Sn wire is especially good at this A trade off of such strong pinning is that when the field density in the magnet bore is sufficiently different than the pinned flux in the windings the flux lines in the superconductor tend to be released and trapped rapidly The field equilibrates during such flux jump events as magnetic field enters or leaves the windings in small avalanches of flux lines This equilibration tends to occur when the field charging direction is reversed at low field magnitudes less than 2 T or when the sign of the field changes Flux jumping subsides at higher fields because the magnet is saturated with flux lines Another aspect of high flux pinning in the magnet is large remanent magnetic fields in the sample space about 100 Oe for the 14 T magnets used currently at Quantum Design which are fabricated using the int
17. Chapter 2 Section 2 2 Installing and Removing the VSM Option 1BInitial Installation of the Hardware and Software o installing the VSM coilset puck o inserting the VSM sample tube o mounting the linear motor transport o completing the electrical connections o installing the MultiVu software application and the VSM software o activating the VSM option o configuring the coilset The complete initial installation of the VSM option should take no longer than an hour In the event that you are performing a partial installation only check the instructions for each phase to be sure that you understand critical aspects of the process 5096 200 MOTOR DRIVE 4096 30 SAMPLE TUBE Figure 2 1 System components for PPMS VSM option Note The general setup of the VSM option will vary between system platforms 2 2 1 Install the Modular Control System and CAN Network Adapter PPMS ONLY You will use the instructions in this section only if a Model 1000 modular control system and the driver software have not yet been installed on your PPMS and PC If your system already has been configured to use Quantum Design modules you can go to Section 2 2 2 To install the Model 1000 CAN network adapter and CAN Manager driver software refer to the Model 1000 Modular Control System User s Manual System Verification After you have completed installation of the Model 1000 and other components perform a verification of the system Q
18. Measurement dialog box Figure 6 14 which organizes immediate mode measurement settings and initiates measurements The dialog has a section showing the measurements three tabs Settings Centering and Advanced and three buttons Start Stop Pause Resume and Close 6 4 2 1 VSM MEASUREMENT DIALOG BUTTONS o The Start Stop toggle button starts and stops the measurement process but it does not close the dialog o The Pause Resume toggle button only stops the system from performing measurements as the system continues to oscillate the sample and execute any scheduled automatic touchdown operations To restart the data output after a Pause click on the Resume Pause toggle button o The Close button closes the VSM Measurement dialog but it does not stop the measurement 6 4 2 2 VSM MEASUREMENT DIALOG LAST MEASUREMENT The VSM Measurement dialog is divided into two Mii x main areas On the left side are the tabs with the Settings Centering Advanced Last Measuremen 1 1 1 1 gt Measure Type 4 measurement settings On the right side is a Last enea Een K Measurement area that displays the most recent Temperature Field Moment and Moment Std Field 77 Oe Error data which are written to the open data file Boe at z p Moment p77 emu o Temperature represents the average Measurement Parameters t temperature during the measurement in Kelvin aka E emu Averaging ime
19. Shoot temperature approach modes for each of the temperature set points in your measurement Restore Defaults The Restore Defaults button resets everything in the dialog to the default settings 6 9 3 5 EXCITATION PARAMETERS Use the options in the Excitation Parameters subsection to set the drive variables for the VSM linear motor transport For more information on Excitation Parameters see Section 6 4 2 5 VSM Data Files Data files have a dat file extension To save VSM measurement data you must open a measurement data file before you start the measurement You designate data files by creating a new one or selecting a pre existing one as is explained in Section 6 4 1 3 6 10 1 Data File Headers The header of a data file contains information such as the title of the data set and the sample properties You have the opportunity to include this information when you create the file this is the only time you can add this information to the data file header Instead after a file has been created you can append comments Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 23 February 2011 Section 6 10 VSM Data Files Chapter 6 VSM Software imi Raw Data View new vsmi1 dat ial xl Header VSM Data File default extension dat Copyright c 2003 Quantum Design Inc All rights reserved TITLE Titanium 1 FILEOPENTIME 1659547667 69 05 21 2003 8 34 am BYAPP VSM 1 0 1 0 NFO PPMS VSM Option Release 0 9 8 Build
20. User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software 6 8 1 Figure 6 19 Setup tab of the sequence mode 6 8 2 Quantum Design Section 6 8 Sequence Mode VSM Moment vs Field Command 1 Field etc so that it is easy to plot the data When you click on the sequence mode Moment vs Field command in the Sequence Commands bar it opens the sequence mode VSM Moment versus Field dialog shown in Figure 6 19 The following describes all of the possible features for this mode Some features may be irrelevant to your system because of magnet type Sequence Mode VSM Moment versus Field Dialog The VSM Moment versus Field dialog has two tabs Setup Figure 6 19 and Advanced Figure 6 20 with options for setting measurement parameters As is explained below the tabs provide several unique functions as well as some of the same functions found in the sequence mode Scan Field and VSM Adv Measure commands You can insert the Moment vs Field command at any time by clicking on the OK button at the bottom of the dialog The Cancel button closes the dialog and does not insert the command or save any changes you have made to the dialog SM Moment versus Field x SM Moment versus Field xi Setup Advanced Setup m Field Sequence entering r Ranging 7 Select Start End Quadrant 3 gt Do Touchdown Centering i
21. VSM motor module which interprets the raw encoder signals from the VSM linear motor transport The VSM detection module detects the in phase and quadrature phase signals from the encoder and from the amplified voltage from the pickup coil These signals are averaged and sent over the CAN bus to the VSM application running on the PC Chapter 5 describes the hardware components of the Quantum Design VSM option in more detail Quantum Design VSM Option User s Manual 1096 100 Rev BO 1 3 February 2011 Section 1 4 Chapter 1 Safety Precautions Introduction to the VSM Option 1 4 Safety Precautions WARNING The VSM option is used in conjunction with the Physical Property Measurement System PPMS family of instruments so you should be aware of the safety considerations for both pieces of equipment Potential safety precautions include those for the use of superconducting magnets and for the use of cryogenic liquids if applicable Consult your base system User Manual for more specifics Above all Quantum Design and its staff ask that you use standard safe laboratory procedures Use common sense Pay attention to the system s state and your surroundings Ifthe behavior of the system appears abnormal something may be wrong with it Investigate and if necessary take appropriate action Supervise inexperienced users and train them in general electrical safety procedures The VSM and PPMS family of
22. epoxy to coat and bind the powder completely Put in evacuation chamber to remove air pockets from mixture Attempt quantitative transfer of mixture to Teflon mold of 4 mm diameter and 5 mm tall The larger brass trough allows a diameter of 6 mm Cure the epoxy in evacuation chamber For some materials placing the mold between the poles of a strong permanent magnet will preferentially align the material along a specific crystallographic axis The epoxy pellet technique is very useful for air sensitive samples and preparation inside the glove box Estimation of the diamagnetic contribution of the epoxy material can be obtained by preparing a sample of equivalent mass The VSM image effect standard is a chip of pure nickel that is potted in an epoxy cylinder and is an example of a mounting technique for irregularly shaped samples For low temperature operation ensure sample does not slip by slightly compressing the brass trough before inserting the sample in it 6 Air reactive and or moisture sensitive samples can be stored in a sealed quartz tube that snaps into the brass trough If a sample is a powder form keep in mind that the sample might move inside the tube while vibrating 7 The process of cleaning brass trough is best accomplished with organic solvent suitable for the dry glue Even though the brass is gold plated strong acidic washes should be avoided in case of scratches While the junction is partly a press fit the use of 3 6 VSM Opti
23. fi K min Stabilize at each Temperature Sweep Continuously Data Acquisition Continuous Measuring Averaging Time g Number of E Temperatures Tel Innere Repetitions at each fi Temperature Keep all measurements m all measurements 50 of measurements 20 of measurements 10 of measurements 5 of measurements 2 of measurements 1 of measurements Estimated Time 02 30 h m Lines 17887 Approx Temperatures 4 Figure 6 28 Setup tab of the sequence mode VSM Moment versus Temperature dialog 6 9 2 Setup Tab SM Moment versus Temperature x Setup Advanced m Centering Ranging g Do Touchdown Centering fat Intervals i f Sticky Autorange Deka po ES C Always Autorange C Fixed Rai Delafield 0 Oe doi 100 mv z Delta 10 Temperature Is C No Automatic Centering PPMS Data Logging Select Advanced Settings Wait Time At Each Step Approach Mode v Require Sweep Mode For Continuous Acquisition o sec Restore Fast ha Defaults M Excitation Parameters Peak mplitude P mm Frequency a0 Hz Maximum Acceleration 126 331 m sec 2 Maximum Moment 10 46875 emu Figure 6 29 Advanced tab of the sequence mode VSM Moment versus Temperature dialog Sequence Mode VSM Moment versus Temperature Dialog The Setup tab Figure 6 28
24. in modules CM A and CM B after ca 2009 OOGOQCO OCC Figure B 3 JB 1 Motor sync connector for the Model CM B VSM detection module Table B 3 JB 1 Motor sync connections for the Model CM B VSM detection module PIN FUNCTION Sync Data Clock PSync Ground Sync Data Clock OoOo NIDII Ri ow pp PSync B 3 2 2 JB 2 MONITOR BNC This connector outputs the amplified pickup coil signal B 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix B Section B 3 Model CM B VSM Detection Module 2BModel CM B Detection Module Front Panel B 3 2 3 JB 3 PREAMP CONNECTOR This connector is the main connection to the preamplifiers and coilset puck It contains two analog inputs for the synchronous detection current and voltage for a thermometer power for the preamp and serial communications to the serial ROM in the preamp box for storing calibration or configuration information OOOO OOO OOOO OOOO OOOO OOD cQ 4A47572721Z72U01 oO o X Figure B 4 JB 3 Preamp connector for the Model CM B VSM detection module Table B 4 JB 3 Preamp connector for the Model CM B VSM detection module PIN FUNCTION 3 Serial C
25. instruments have safety features to prevent accidents from causing injury or serious equipment damage f you use the equipment in a manner that is not specified by Quantum Design the protection afforded by the equipment may be impaired 1 4 1 Magnets WARNING Any person who wears a pacemaker electrical medical device or metallic implant must stay at least 5 m 16 5 ity from the dewar In addition personnel should keep all ferromagnetic objects at least 5 m 16 5 ft from the dewar Verify that all magnetic fields are at zero 0 before you handle the VSM linear motor transport in any way The following precautions should be followed to ensure the safety of personnel who work with or around a superconducting magnet This material is covered in more depth in your system User Manual Verify that any person who has a metallic implant or is wearing a pacemaker or electrical or mechanical medical device stays at least 5 m 16 5 ft from the dewar Large magnetic fields At the current time August 2010 5 m should be a large enough distance to protect wearers of metallic implants or medical devices from most magnetic fields produced by Quantum Design magnets However the safe distance from newer magnets in development could be greater Please consult Application Note 1070 204 on the Quantum Design website www qdusa com for detailed information about stray magnetic fields from the magnets in use 1 4 VSM O
26. opens the VSM Install Remove Sample Wizard Figure 6 5 o To provide the software with the location of the sample select Sample gt gt VSM Manual Locate The Specify Sample Location dialog will open so that you can enter the sample offset or perform an automatic scan This dialog also appears when you use the VSM Install Remove Sample Wizard to install a sample Section 4 3 3 PPMS Multivu Simulation Mode File View Sample Sequence Measure Graph Instrument Utilities Help Selected 5 Sequence2 s YSN Ren T Sequence Ste VSM Manual Locate equence Idle VSM Install Remove Sample Wizard x M Chamber Status 5 Pause ROK Stable Sealed Abort Lock Instructions Press Open Chamber to do the following things Bring the sample chamber to room temperature Vent the sample chamber Move the transport to load position Otherwise press Skip gt gt Open Chamber Use Extended Purge lt lt Back Skip gt gt Cancel Figure 6 5 The Specify Sample Location dialog that opens from the dropdown menu when you select Sample gt gt VSM Manual Locate 6 3 3 Measure If a sample has been installed in the VSM you can use the Measure dropdown menu at the top of the MultiVu window Figure 6 6 to open immediate mode VSM measurement dialogs e g for setting up and taking measurements for centering the sample and for adding a comment to an output data fil
27. or 4096 675 Sample Rods 4096 352 Figures 2 1 5 6 4096 610 4096 275 or 4096 276 Sample Holders paddle shaped 4096 392 p 3 4 Sample Holders trough shaped 4096 391 p 3 5 VSM Powder Capsule pieces 4096 387 p 3 6 Quartz braces for brass trough 4096 399 Preamp Cable Assembly 3096 300 01 or Figures 2 1 2 8 5 9 3096 300 02 Motor Drive Cable 3096 200 or Figures 2 1 2 8 5 10 3096 201 Model CM A Motor Module 4101 100 Figures 2 1 2 8 5 11 Model CM B VSM Module 4101 150 Figures 2 1 2 8 5 12 Model 1000 Modular Control System 4100 001 Figures 2 1 5 13 VSM Option User s Kit 4096 100 Figure 5 7 This item might be pre installed This item is shipped in the VSM Option User s Kit This item might be pre installed in the system This item is for the PPMS VersaLab and Dynacool have system incorporated module towers Installation Process In the event that you are performing a complete initial installation 1 e no components were installed at the factory the process includes the following phases o installing and verifying the modular control system CAN network adapter and CAN driver software if no other CAN based measurement options have been previously installed on your system o inserting the control modules o warming the sample chamber setting the magnetic field to zero and venting the sample chamber 2 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011
28. sets the VSM to uniformly EE B space data collection with respect to the magnitude of the um meanremens magnetic field Figure 6 24 Data Acquisition Data spacing selection o Uniform Spacing in Field 2 sets the VSM to uniformly space data collection with respect to the square of the magnitude of the magnetic field o Uniform Spacing in Field 1 2 sets the VSM to uniformly space data collection with respect to the square root of the magnitude of the magnetic field o Uniform Spacing in 1 Field sets the VSM to uniformly space data collection with respect to the inverse of the magnitude of the magnetic field o Uniform Spacing in Log Field sets the VSM to uniformly space data collection with respect to the logarithm of the magnitude of the magnetic field Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 15 February 2011 Section 6 8 Sequence Mode VSM Moment vs Field Command Chapter 6 VSM Software gt Data Acquisition A veraging Time Uniform Spacing in Field x The Averaging Time text box Figure 6 25 allows you to set the Averaging Time fi sec length of time the VSM will collect data before it is averaged into C Number of Fields p a measurement See Section 6 4 2 3 for more information about addis Averaging Time 2 Os 7 P Repetitions at fi Number of Fields Min to Max and Field Increment each Field P K all measurements When you are not using Continuous Measuring you must itus define the s
29. supplied computer and monitor for additional safety warnings and notices before you operate the system Regulatory Information Oo o This apparatus has been tested to the requirements of the EMC Directive 89 336 EEC This apparatus is defined as ISM Group 1 Class A and B equipment per EN 50011 1991 industrial and light industrial environment limits of radio frequency emission This apparatus has been tested to the requirement of the Low Voltage Directive 73 23 EEC See the EU Declaration of Conformity for additional regulatory information regarding your PPMS Quantum Design VSM Option User s Manual 1096 100 Rev BO iii February 2011 C ONTENTS Table of Contents PREFACE Contents and Conventions desees paene va eo ed nena ehe ua cdssvusslsuavecaucssoovaslestouressausvuadsanvueus XV Poly Tntroducttohi c oo hio ee dete esed te ee edad tee deste Maas condones XV P2 Scopeof the Man l need eerte tete e e n ite cote sn itd XV P3 Contentsof the Manual 4 iore adde deor pee att orb XV P 4 Conventions in the Manual sererek ORFAS EAEE e AEE Neee xvi CHAPTER 1 Introduction to the VSM Option esssesssoessocesooessocessccssocesocesoooesoocesseessccesocssoosssossssesssecssoose 1 1 T Introduction eee eer ee ttn eerte ioter ied 1 1 132 Overview or th VSM Option dite tie eicere a a ebbe etr o irri be b ta lace 1 1 12 T What TC MeasUures 5 uec eec den etre eee e eat oie eid tee eic Bede 1 1 1 2 2 Notabl
30. that you select multiple nested software options dat The Courier font indicates file and directory names and computer code Important Text is set off in this manner to signal essential information that is directly related to the completion of a task Note Text 1s set off in this manner to signal supplementary information about the current task the information may primarily apply in special circumstances CAUTION Text is set off in this manner to signal conditions that could result in loss of information or damage to equipment WARNING Text is set off in this manner to signal conditions that could result in bodily harm or loss of life WARNING Text is set off in this manner to signal electrical hazards that could result in bodily harm or loss of life xvi VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 C H A P T E R 1 Introduction to the VSM Option 1 1 1 2 1 2 1 1 2 2 e Introduction This chapter contains the following information o Section 1 2 presents an overview of the o Section 1 4 outlines major safety VSM option considerations for working with the system o Section 1 3 discusses the VSM theory of o Section 1 5 contains information on how operation to contact your Quantum Design service representative Overview of the VSM Option What It Measures The Quantum Design Vibrating Sample Magnetometer VSM option for the Physical Prope
31. the Close Chamber button IMPORTANT do not perform any CPU intensive tasks on the computer while the touchdown operation completes 9 Youcan now set up the system to perform sample measurements Quantum Design VSM Option User s Manual 1096 100 Rev BO 4 5 February 2011 Section 4 4 Chapter 4 Taking Immediate Mode VSM Measurements Taking VSM Measurements 4 4 Taking Immediate Mode VSM Measurements After the sample has been installed and the position of the sample has been specified you can perform VSM measurements by using immediate mode commands e g from command buttons or dropdown menus or by constructing sequence files This This provides a quick start guide for immediate mode measurements Chapter 6 describes sequence measurements and explains the parameters in the dialogs 4 4 1 Measure Command and VSM Measurement Dialog To specify parameters for VSM measurements click on the Measure button in the VSM Control Center For most situations the default settings for VSM measurement should be kept e Continuous Measuring will make best use of the fast lock in based VSM measurement by streaming data continually e Averaging Time second will provide 10 emu noise levels and the speed will allow rapid field sweeping during measurements e Logging Interval 0 will write all the measurements to the output data file instead of reducing the file size by only recording data at the stated interval e In Centering tab Do Touc
32. the fragile quartz paddle is designed for the lowest moment samples a more robust brass trough provides versatility A The quartz paddle is redrawn from a 4 mm diameter rod Elimination of surface microcracks improves mechanical strength of the quartz paddle A nitric acid dip removes surface impurities Smooth surface can make cleaning easy but reduces adhesion of glue The adapter is made of glass filled polycarbonate which should never be exposed to organic solvents especially acetone The outer gluing surfaces of the quartz pieces are sanded to help bind with the epoxy A complimentary shaped shim is added to the paddle and put inside the adapter containing epoxy resin The epoxy is specially chosen to withstand both high temperatures 400 K and cryogenic conditions The assembly is cured straight in a custom fixture 1 For mounting thin films parallel to field see figure to the left do not exceed the width of the paddle Wider samples can be mechanically secured and better protected using the brass trough or aluminum frame techniques Place the quartz holder in mounting station Using a sharp wooden stick or other tool place a small drop of glue on the paddle set film on top and press to secure bond Let it dry completely at ambient conditions If the sample can handle the heat increase temperature to 340 K and purge sample chamber Return to 300 K purge and seal or lower temperature and follow centering routine To remove sample hol
33. the sample center changes with temperature and its importance in temperature dependant magnetic measurements Overview This chapter discusses some issues artifacts or noise that can arise when making VSM measurements and describes ways of mitigating or preventing the issues Most of the material in this chapter is taken from VSM application notes that are posted on the Quantum Design website www qdusa com and have thus been incorporated into this user manual It is useful to classify the measurement artifacts into two classes 1 those that affect the accuracy of the reported moment and 2 those that affect the precision 1 e the noise level While poor precision will often be easy to recognize high values of M Std Err and noise in the Moment value it is more challenging to determine if the moment is being reported accurately Below are some important topics to consider when troubleshooting VSM data To help you decide the relevance of each to your particular data the section starts with a list of common symptoms associated with this issue Quantum Design VSM Option User s Manual 1096 100 Rev BO 7 1 February 2011 Section 7 3 Chapter 7 Vibration of the Detection Coil Set Troubleshooting 7 3 Vibration of the Detection Coil Set Symptoms e noisy moment at high fields e features in M H like unexpected curvature or shifts e heating at low temperatures which occurs only when sample is oscillating In a VSM it is imp
34. the tape is evenly distributed in the background there will be no contribution to the reported moment of the sample To replace common drinking straws Kapton tubing is available through the medical community and may provide flexibility in diameter selection with lowest level of impurities Organic solvents like toluene or maybe iso propanol IPA can help dissolve the glue remaining on the holder after tape is removed Thin Teflon tape can be wrapped around the quartz holder to secure the sample location without use of glue However the technique tends to produce a significant paramagnetic oxygen peak around 50 K As a precaution add a heat and purge step to the sequence The Teflon tape can cover the full temperature range of the instrument but 350 K is usually sufficient for this purpose When Teflon becomes a point source dipole like when wrapping the sample a more significant ferro magnetic contribution is measured Each batch should be tested for impurities The standard Parafilm roll and various wax materials can be used to secure the sample Watch maximum exposure temperatures of the wax These types of materials are typically low moment background and useful with air sensitive samples or when recoverability is desired 3 Custom mounting techniques for classes of samples Note that following techniques may not apply to all platforms 3 8 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 3 Secti
35. vs Temp command Section 6 10 describes the format of VSM data files 6 2 Activating and Deactivating the VSM Option 1 Quantum Design To activate the VSM application and open the VSM Control Center select Utilities gt gt Activate Option from the dropdown menu of the MultiVu window Figure 6 1 VSM Option User s Manual 1096 100 Rev BO 6 1 February 2011 Section 6 2 Chapter 6 Activating and Deactivating the VSM Option VSM Software LIIS MultiVu Simulation Mode File View Sample Sequence Measure Graph Instrument Utilities Help Eg Ei ee Hael amp s amp Activate Option x Configure Option Option Manager Log PPMS Data Available Options Active Options Upload ACMS Send GPIB Commands Heat Capacity Activate Magnet gt Helium3 EUIMEPTSEEPUE EM Resistivit mS Error Handling Event Log Connection Sigma Log PPMS Data Diagrams l Fil Status Calculator EverCool gt Figure 6 1 Using the MultiVu dropdown Utilities menu and Option Manager to activate the VSM Option 2 When the Option Manager dialog opens select VSM and click on the Activate button This will move the VSM option from the Available Options section of the dialog to the Active Options section The VSM Control Center and the VSM Log window will open concurrently When running in simulation mode the VSM Control Center is titled VSM SIM see Figure 6 2 To deactivate the VSM opti
36. 399 Ni image effect assembly potted Powder capsules bag of 50 pairs 100 pieces Pd standard assembly in brass trough Brass trough sample holder Quartz paddle sample holder Quartz rod sample brace for brass trough Quantum Design VSM Option User s Manual 1096 100 Rev BO 3 9 February 2011 Section 3 3 Mounting Samples 4096 630 4096 635 4999 903 4096 030 4097 035 LBC brass trough LBC aluminum paddle Dy203 assembly in brass trough GE 7031 varnish Zircar AL CEM alumina cement ACA 6 Duco cement ATK1 025 Kapton tape 0 001 thick x 0 25 wide Please contact your local Quantum Design representative for sales inquiries Chapter 3 Sample Preparation and Mounting Securing agents from the left 2 part epoxy Duco cement ZircarCement GE7031 Varnish fast curing 3 10 Superglue slower curing Superglue Kapton tape VSM Option User s Manual 1096 100 Rev BO February 2011 Quantum Design C HAPTER 4 Taking VSM Measurements 4 1 4 2 Introduction This chapter contains the following information o Section 4 2 summarizes the o Section 4 4 describes how to take measurement process when you use immediate mode measurements with the the Quantum Design VSM option VSM option o Section 4 3 describes how to install samples for taking VSM measurements Overview of VSM Measurements A VSM measurement consists of a sequence of centering operations followed by the oscillation of the
37. 5V 3 Encoder Input A 4 Encoder Input B 5 Unused Encoder Input Z 6 n c 7 n c 8 Motor Max Limit Switch 9 Motor Min Limit Switch 10 Motor 11 Ground 12 Encoder Input A 13 Encoder Input B 14 Unused Encoder Input Z 15 n c 16 n c 17 Motor Max Limit Switch Rtn 18 Motor Min Limit Switch Rtn 19 Serial Com Data Out 20 Serial Com Data Input 21 Serial Com Clock 22 Serial Com Select 1 23 Serial Com Select 2 A 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix A Section A 3 Model CM A VSM Motor Module 2BModel CM A VSM Motor Module Front Panel A 32 2 JA 2 STEPPER CONNECTOR The stepper connector is available for future expansion You must contact Quantum Design before you attempt to use the connector A 32 3 JA 3 MOTOR SYNC CONNECTOR This connector outputs the motor encoder position as a high speed digital serial signal This would normally be connected to a synchronous detection module such as the Model CM B VSM module Important This sync connector and the short crossover sync cable 3096 400 to module CM B are no longer used in newer versions of firmware in modules CM A and CM B after ca 2009 COO COGO JOO E A O Oo Figure A 4 JA 3 Motor sync connector for the Model CM A VSM motor module Table A 4 JA 3 Motor sync connector for the Model CM A VSM motor module PIN FUNCTION Sync Data Clock
38. 600 with arrows to Figure es Installing the VSM coils t puck coilset serial number and to mounting ring for attaching the puck with the puck insertion tool insertion tool 2 2 4 Insert the Sample Tube The sample tube contains low friction bearing sleeves to center the sample rod in the bore of the coilset Figure 2 4 shows the sample tube assembly where you can see that the top of the sample tube assembly includes an integrated centering ring and a stabilizer post When the sample tube has been inserted into the sample chamber the stabilizer post will extend into both the sample chamber and the extender tube flange on the VSM linear motor transport as is shown in Figure 2 5 The primary functions of the post are to act as a guide when the transport is installed and to keep the transport on the system See Chapter 5 for more information on the sample tube INTEGRATED CENTERING RING vy SAMPLE TUBE STABILIZER POST BAFFLES Qo op OO CENTERING x PROBE HEAD BAFFLE Figure 2 4 VSM sample tube assembly 4096 301 is shown for DEWAR E example x A Figure 2 5 Inserting the VSM sample tube into the sample chamber Quantum Design VSM Option User s Manual 1096 100 Rev BO 2 5 February 2011 Section 2 2 Chapter 2 1BInitial Installation of the Hardware and Software Installing and Removing the VSM Option Use the steps below to install the sample tube assembly 1 Verify th
39. 6889 0 6647 10 1 0 6988 0 6914 0 6669 10 2 0 7070 0 6993 0 6737 10 3 0 7213 0 7130 0 6854 Table 3 1 only addresses pointlike and cylindrical samples but you can obtain similar results when you measure samples with other shapes In such cases use Table 3 1 as a rough guide to approximate the expected errors Again detection coil sensitivity for the included palladium VSM standard sample 4096 390 is not necessarily the same as detection coil sensitivity for samples with shapes and or sizes that differ from the included palladium standard sample The VSM measurement software will not correct for such differences 3 2 2 Errors from Radial Offset of Sample You also should consider the radial centering of the sample in the coilset when the absolute accuracy of VSM measurement results is important Table 3 2 shows the calculated effect of radial offset for cylindrical samples of different sizes using oscillation amplitudes of 1 mm and 2 mm Note that when the centering error is only 1 mm there could be as much as 1 error in the repeated moment 3 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 3 Section 3 3 Sample Preparation and Mounting 2BMounting Samples 3 2 3 3 3 3 3 1 Table 3 2 Calculated ratio of the reported moment to the true moment of cylindrical samples for different radial offsets from the coilset centerline PEAK SAMPLE AMPLITUDE DI
40. Advanced Material LEEPER Comment stock sample 1 Additional Descriptive Comments Mass o mg Size Volume mm Shape iregular Melecur Weight Status Measure Help VSM Ready Figure 6 12 Sample tab in the VSM Control Center 6 4 1 4 ADVANCED TAB The Advanced tab Figure 6 13 organizes support for troubleshooting for example checking calibrations and troubleshooting system performance Hence you will use the options on the Advanced tab only if you are an experienced VSM operator o The Units of Measure options allow you to record in emu or in A m ampere meters squared By default the measures are recorded as emu o The Motor Friction Scan button moves the VSM linear motor transport through the full range of motion The system plots the motor force as current as a function of position for both lifting the sample and lowering the sample A difference between these two curves indicates friction due to ice or other obstructions VSM SIM No Datafile Install Data File Sample Advanced Simulation Units of Measure PEGN pere O amp m2 Status VSM Ready Figure 6 13 Advanced tab in the VSM Control Center Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 7 February 2011 Section 6 4 Chapter 6 VSM Control Center VSM Software 6 4 2 VSM Control Center Measure Button The Measure button in the VSM Control Center opens the VSM
41. Application Note 1096 303 Symptoms e noise in both Moment and M Quad Signal e noise level scales with the magnitude of the moment e noise that abruptly starts or stops as a function of temperature Precise VSM measurements require smooth sinusoidal motion of the sample within the pickup coils Deviations from this ideal motion will produce artifacts in the measured magnetic moment of the sample This can occur in the following cases e A sample is not held tightly in the sample holder and subsequently it rattles e A powdered sample is not packed tightly and the material shakes within the sample holder e A glue joint on the sample rod is loose so that the sample holder slips Figure 7 4 shows magnetic moment vs temperature data from a nickel sphere 2 mm in diameter measured in a magnetic field of 1 tesla The moment is very large 3 5 emu and at temperatures below about 290 K its behavior is noisy and erratic based on the following observations Image_00001 dat DER The moment data exhibits significant noise and jumps The quadrature signal M Quad Signal which describes any coilset pickup that is not in phase with the motion of the motor is a significant fraction 5 of the moment signal The standard error M Std Err which describes the uncertainty in the reported moment value is scattered Moment emu In contrast at temperatures above 300 K the moment data is smooth and the quadrature signal and
42. Design February 2011 Appendix B Section B 4 Model CM B VSM Detection Module 3BModel CM B Detection Module Rear Panel B 4 3 QD CAN Connector The QD CAN connector is the main communication connection for controlling the Model CM B VSM detection module The CAN network signals CAN High CAN Low are connected to all other CAN modules on the bus and to the PC Power 24 volts reset and sync signals also are sent to the module though this connector JJV OOOO EN Figure B 6 QD CAN connector on rear of the Model CM B VSM detection module Table B 5 QD CAN connector on the rear of the Model CM B VSM detection module PIN FUNCTION as 24 V CAN Low Power Return 24V Sync Low Line Sync System Ground CAN High Sync High Reset 24 V DC oO oO N I oi oa AIIIN Quantum Design VSM Option User s Manual 1096 100 Rev BO B 7 February 2011 A PP E NDIX C Application and Service Notes VSM Application notes expand upon the technical content of the user s manual They serve the function of training the user on topics such as sample mounting measurement protocol and data interpretation and also of warning the user about understanding and preventing artifacts in the resulting data Service notes by contrast outline procedures for instrument maintenance testing and modification Note that existing application a
43. M System dialog page 1 4 Verify that the number in the text box matches the serial number of your detection coilset puck If no number is displayed as above enter the serial number of your detection coilset puck in the text box 5 Click on the Next gt gt button at the bottom of the dialog box Page 2 of the Configure VSM System dialog Figure 2 13 will open showing the results of system tests to verify system operations Configure SM System x Test Again V5M System Test Results Testing Coilset OK il Limits Found OK Back Lee Cancel Figure 2 13 Configure VSM System dialog page 2 Testing calibration file 6 When the report in the VSM System Test Results area is complete and no errors are reported click on the Finish button The Configure VSM System dialog will close and you will be back at the VSM Control Center and the Install tab 7 Ifyou have completely followed the VSM hardware and software setup steps the system is now ready for you to mount a sample install it in the cryostat and perform VSM measurements as is explained in Chapters 3 and 4 First please review Section 1 4 Safety Precautions for important information Quantum Design VSM Option User s Manual 1096 100 Rev BO 2 11 February 2011 Section 2 3 Chapter 2 Removing the VSM Option Installing and Removing the VSM Option 2 3 Removing the VSM Option WARNING Verify that there are no nearby sour
44. MENSIONS SAMPLE RADIAL GEFSET A mm L mm D mm 0 mm 0 5 mm 1 0 mm 1 5 mm 2 0 mm 1 0 1 0 1 0 1 000 1 001 1 003 1 003 0 997 1 0 2 0 2 0 1 000 1 001 1 003 1 005 1 000 1 0 3 0 3 0 1 001 1 003 1 006 1 009 1 006 2 0 1 0 1 0 1 000 1 002 1 010 1 020 1 028 2 0 2 0 2 0 0 999 1 002 1 010 1 020 1 030 2 0 3 0 3 0 0 998 1 001 1 010 1 023 1 035 Size of Magnetic Moment The magnetic moment of your samples should be larger than about 10 emu to be detected in the VSM Mounting Samples Accurate Sample Location The VSM system uses a touchdown technique for automatic centering of the sample in the detection coils This technique is described in detail in Chapter 4 To optimize the touchdown take special care with two steps in your preparations o Venfy that the sample is mounted on the sample holder near 35 mm from the bottom of the sample holder Quantum Design has provided you with a special sample mounting fixture see Figures 4 2 and 5 8 for locating the sample o Verify that the end of the sample holder has a very well defined contact surface for performing the touchdown operation Quantum Design recommends that you locate the sample at an offset of 35 mm The height of the coilset is about 40 mm so the offset of 35 mm places the end of the sample holder 5 mm above the puck surface This location is far enough from the end of the sample holder so that end effects are minimal yet it safely allows up to 4 mm o
45. SM Moment versus Field dialog 6 14 Data Acquisition Data spacing selection eeeeeeeeeereeeee 6 15 Data Acquisition Number of Fields and Field Increment 6 16 Data Acquisition Keep and Approximate Fields settings ssessse 6 16 Advanced Settings Advanced tab Require sweep and so on sse 6 17 Setup tab of the sequence mode VSM Moment versus Temperature dialog 6 19 Advanced tab of the sequence mode VSM Moment versus Temperature dialog 6 19 Temperature Control section of the sequence mode VSM Moment versus Temperature dialog 3 ie eret eee tete ote ioc ee cta 6 19 Data Acquisition section of the sequence mode VSM Moment versus Temperature dialog re Rente ce RU etd De 6 20 Data Acquisition section Keep and so on seseeeeeenenen e 6 21 Advanced Settings section Require sweep and so on sse 6 22 Raw Data view of a VSM data file sse ener 6 24 VSM Option User s Manual 1096 100 Rev BO xi February 2011 Contents Table of Figures Figure 7 1 Figure 7 2 Figure 7 3 Figure 7 4 Figure 7 5 Figure 7 6 Figure A 1 Figure A 2 Figure A 3 Figure A 4 Figure A 5 Figure A 6 Figure A 7 Figure B 1 Figure B 2 Figure B 3 Figure B 4 Figure B 5 Figure B 6 xii VSM data file showing change in sample positi
46. Temp command to rapidly set the VSM to take data while sweeping temperature in a variety of different patterns You also can control when data is taken with respect to temperature increment e g uniform spacing in Log Field or 1 Field which facilitates plotting the data When you click on the sequence mode Moment vs Temp command in the Sequence Commands bar the sequence mode VSM Moment versus Temperature dialog opens Figures 6 28 and 6 29 6 9 1 Sequence Mode VSM Moment versus Temperature Dialog The VSM Moment versus Temperature dialog has two tabs Setup Figure 6 28 and Advanced Figure 6 29 Use the Setup tab to set the parameters for a variable temperature measurement Use the Advanced tab to control other aspects of the measurement such as the temperature approach mode 6 18 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software Section 6 9 Sequence Mode VSM Moment vs Temp Command As is explained below the tabs have several unique functions as well as some of the same functions found in the sequence mode Scan Temperature and VSM Adv Measure commands You can insert the Moment vs Temp command at any time by clicking on the OK button at the bottom of the dialog box The Cancel button closes the dialog and does not insert the command SM Moment versus Temperature x Setup Advanced Temperature Control Start 200 K End rs K Sweep Rate
47. The VSM linear motor transport will perform a Home or homing operation During a homing operation the system finds the full range of travel for the transport by going through a full travel cycle The cycle ends at the top in the sample load position The View Sample and Measure menus on the MultiVu menu bar will show VSM specific features For example the Status bar at the bottom of the VSM Control Center Figure 2 10 reads VSM Ready and VSM specific commands are accessible on the Measure dropdown menu Figure 2 11 See Chapter 6 for a full description of the VSM software VSM Option User s Manual 1096 100 Rev BO 2 9 February 2011 Section 2 2 Chapter 2 1BInitial Installation of the Hardware and Software Installing and Removing the VSM Option 2 2 8 2 10 PPM Multivu Simulation Mode iol xl File View Sample Sequence Measure Graph Instrument Utilities Help Aleli o e S gt ale Vibrating Sample Magnetometer Initializing 7 17 2003 10 02 42 4M Resetting CAN controller board Initializing Motor module Module name Quantum Design VSM Linear Motor Servo Controller HW Version 3101 100 40 SW Version 01 00 03 Initializing VSM module VSM SIM No Datafile Install Data File Sample Advanced Chamber Status 1 90K Stable Purged and sealed Install Remove Configure VSM Sample System Status Measure Help WSM Ready Figure 2 10 VSM Control Center and
48. The kit includes the following contents o Sample Mounting Station The sample mounting station is used to mount samples at the correct location in the sample holder For more information about mounting samples see Figure 5 8 and Section 3 3 o Sample Holders Sample holders are used to hold samples see Figure 5 8 the holders screw onto the bottom of the VSM sample rod Quantum Design has provided five paddle shaped sample holders and five trough shaped sample holders o Calibration Sample The palladium calibration sample is used to calibrate the VSM option and to verify its accuracy o Coilset Assembly The VSM coilset assembly is shipped as part of the VSM Option User s Kit PALLADIUM CALIBRATION COILSET SAMPLE ASSEMBLY AMPLE NTINC TATION PADDLE SHAPED SAMPLE HOLDERS TROUGH SHAPED SAMPLE HOLDERS Figure 5 7 VSM Option User s Kit 4096 100 Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 7 February 2011 Section 5 5 Chapter 5 VSM Electronics VSM Hardware 5 4 Sample Mounting Station The sample mounting station 4096 110 is used to precisely locate and measure within 0 5 mm the sample offset which is the distance between the sample and the bottom of the sample holder see Figure 5 8 SAMPLE HOLDER SLIDE TO RIGHT TC RELEASE OR LOAD SAMPLE JLDER Figure 5 8 Sample mounting station 4096 110 The VSM measurement algorithm requires an accurate measurement of this distan
49. VSM Moment vs Field Command Sweep The Sweep radio button sets the magnet to continuously change the field without pause during the measurement When this setting is used the VSM will collect data at each field shown in the Approximate Fields list End Mode The End Mode dropdown menu bar allows you to set the state Persistent or Driven that the magnet will be in after the measurement has ended For more information about End Mode CAUTION For liquid He based systems monitor the system closely when it is in Driven mode Use of Driven mode significantly increases heat flow into the dewar and the helium boil off rate so there is an increased risk of a magnet quench 6 8 2 3 DATA ACQUISITION SETTINGS Use the Data Acquisition section Figure 6 24 to set the basic parameters of the moment versus field measurements Data Spacing The Data Spacing dropdown menu bar at the top of the section Data Acquisition provides the following options Continuous Messun o Continuous Measuring sets the VSM to take data in Continuous Measuring Uniform Spacing in Field Continuous Measuring mode When you are not using Uniform Spacing in Field 2 Continuous Measuring you must define when the VSM flyer nei eile will take data by designating the field increment between Uniform Spacing in Log Field measurements as is explained below in Number of Fields Min to Max and Field Increment Repetiti i iste EIE o Uniform Spacing in Field
50. VSM Log window AA PPMs Multi u Simulation Mode Fie View Sample Sequence Measure Graph Instrument Utilities Help oleje sje i VSM Datafile Comment Figure 2 11 PPMS MultiVu menu bar and Measure dropdown menu for VSM option 5 Next you will verify the serial number on the detection coilset puck and test the coilset thermometer and system calibration Configure the VSM System The serial number of the detection coilset puck identifies the calibration file that is used to calibrate the coilset You must verify that the serial number on the puck which you obtained in Section 2 2 4 matches the standard calibration file referenced in the software You will use the Configure VSM System dialogs to specify the puck serial number and test the VSM hardware 1 Locate the puck serial number that you obtained in Section 2 2 3 2 Click on the Configure VSM System button which is located on the right hand side of the Install tab Figure 2 10 3 Page 1 of the Configure VSM System dialog will open Figure 2 12 Note the text box where you will enter the serial number of the standard VSM calibration file VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 2 Section 2 2 Installing and Removing the VSM Option 1BInitial Installation of the Hardware and Software Configure vam system x View Diagram Enter Coilset Puck Serial Number Back Cancel Figure 2 12 Configure VS
51. a coupling constant m is the DC magnetic moment of the sample A is the amplitude of oscillation and fis the frequency of oscillation The acquisition of magnetic moment measurements involves measuring the coefficient of the sinusoidal voltage response from the detection coil Figure 1 1 illustrates how this is done with the VSM option 1 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 1 Section 1 3 Introduction to the VSM Option Theory of Operation VSM HEAD LINEAR MOTOR MOTOR DRIVE CURRENT I I if MOTOR MODULE SERVO CONTROL Na ni RAW ENCODER SIGNAL DRIVEN SAMPLE ROD ENCODER POSITION SAM PICK UP COILS Ta Figure 1 1 Operating principle for the VSM option VSM MODULE COILSET VOLTAGE Yra SYNCHRONOUS DETECTION The sample is attached to the end of a sample rod that is driven sinusoidally The center of oscillation is positioned at the vertical center of a gradiometer pickup coil The precise position and amplitude of oscillation is controlled from the VSM motor module using an optical linear encoder signal readback from the VSM linear motor transport The voltage induced in the pickup coil is amplified and lock in detected in the VSM detection module The VSM detection module uses the position encoder signal as a reference for the synchronous detection This encoder signal is obtained from the
52. alibration file 2 11 The touchdown centering operation sese 4 2 Reading the position of the sample from the sample mounting station 4 3 Example of a centering scan for a sample with a large positive magnetic moment 0L 2 EIUS t eee eE E eto eaten ctu techs hese ee Ert ce et ee rr emet dtt ee Ec evene 4 5 The VSM Install Wizard final page 0 2 cece eecceeeeeeeeeeeeeeeeeseecaeecaaecaecsaeseaeenaeens 4 5 The VSM Measurement Dialog eese nennen rennen 4 7 VSM linear motor transport 4096 400 isses enne 5 2 Storage case 4096 150 for the linear motor transport eeeeses 5 3 Coilset puck 4096 204 e ether reet eere e OS e e er eere E ERES 5 4 The internal dimensions of a standard coilset puck esse 5 4 VSM sample tube 4096 301 shown for example seen 5 6 VSM sample rod 4096 352 shown for example sse 5 6 VSM Option User s Kit 4096 100 esses nennen enne 5 7 Sample mounting station 4096 110 sss 5 8 Preamp cable assembly 3096 300 sss eene enne 5 8 Motor drive cable 3096 200 eterniie eene enne in a ennt enne 5 9 Model CM A VSM motor module 4101 100 esee 5 9 Model CM B VSM detection module 4101 150 essere 5 10 Model 1000 modular control system 4100 001
53. alling a Sample VSM Install Remove Sample Wizard Xi Sample Holder Coordinates for Center Position Sample Holder Offset a379 mm lt Scan for Sample Offset 1 5 P3 Enter Offset manually 10 E 7 ss ips ps up x T p i Advanced Centering Sample Offset mm lt Back Cancel Figure 4 3 Example of a centering scan for a sample with a large positive magnetic moment of 2 emu Moment emu 7 Click on the Next gt gt button at the bottom of the dialog Figure 4 3 This button opens the last page of the VSM Install wizard Figure 4 4 which reports the sample offset position and related instructions SM Install Remove Sample Wizard Chamber Status 305 K Stable Purged and sealed M Instructions You have entered a sample offset position of 33 79 mm for touchdown centering Make sure the cap is on the transport and press Close Chamber to obtain the initial touchdown position and purge the sample chamber You may select a normal purge seal or an extended purge Close Chamber J Use Extended Purge lt lt Back rn Cancel Figure 4 4 The VSM Install wizard final page Select Use Extended Purge any time you plan to use low temperatures T lt 270 K Note that this 10 minute extended purge must complete before measurements of temperature variations are started 8 Place the cap on the linear motor transport and click on
54. and a thermometer for monitoring the sample temperature You will insert the coilset puck into the sample chamber by using the PPMS sample insertion tool also called the puck insertion extraction tool and the same procedures used to insert other types of pucks see the Physical Property Measurement System Hardware Manual for information on puck insertion and extraction You must install the puck before you insert the sample tube Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 3 February 2011 Section 5 2 VSM Hardware Components The electrical connector at the bottom of the coilset puck has a serial number see Figure 5 3 As explained in Sections 2 2 3 you will use this serial number to verify the numbers contained in the application software The system uses the serial number to identify the puck calibration information The VSM option is flexible enough to accommodate different detection coil configurations all you will need to do is change the coilset puck However for most uses the standard coilset puck provides the best trade off between sensitivity and accuracy The dimensions of the standard coilset puck are shown schematically in Figure 5 4 The center of the gradiometer pick up coils is located 40 1 mm 1 58 in above the location corresponding to the puck surface This position corresponds to the center position of PPMS high field systems 14 T or greater and the high homogeneity region of low
55. and stable fields when using a 14 T magnet at fields between 2 T to 2 T Quantum Design VSM Option User s Manual 1096 100 Rev BO 7 9 February 2011 Section 7 6 Performing VSM Measurements in PPMS High Field 14T or Higher Magnets 7 10 Chapter 7 Troubleshooting Thus Quantum Design strongly advises users to measure moment versus field in a stepwise manner and perform measurements only at stable fields when measuring between 2 T to 2 T In the event that a user would like to sweep the field over the full range in a 14 T magnet below is a model for constructing a sequence file that helps minimize flux jumps SEQUENCE MODEL M H FROM 14 TESLA TO 14 TESLA VSM M H command 14 tesla to 2 tesla 100 Oe sec SWEEP mode end mode driven measu re continuous VSM M H command 2 tesla to 2 tesla 100 Oe sec DRIVEN AT EACH FIELD mode end mode driven Uniform spacing in field VSM M H command 2 tesla to 14 tesla 100 Oe sec SWEEP mode end mode driven measu re continuous Set Field 0 0 end mode persistent VSM Option User s Manual 1096 100 Rev BO February 2011 Quantum Design A P PEN DIX A Model CM A VSM Motor Module A 1 Introduction This appendix contains the following information o Section A 2 provides a functional overview o Section A 4 describes the back panel and of the Model CM A VSM motor module relevant components of the Model CM A including a block diagram a
56. at the standard centering ring has been removed from the top of the system A VSM specific centering ring assembly has been integrated into the VSM sample tube assembly Important You cannot use a standard centering ring between the VSM linear motor transport and the sample chamber As a safety mechanism the VSM system cannot be installed on the system without the VSM specific components such as the VSM sample tube assembly with its integrated centering ring and stabilizer post 2 Examine the O ring on the sample tube centering ring for dust or dirt If it is dirty clean it and lightly grease it with silicone vacuum grease 3 Using Figure 2 5 as a guide carefully lower the sample tube assembly into the sample chamber until the VSM centering ring seats onto the top flange 2 2 5 Mount the VSM Linear Motor Transport WARNING Verify that there are no nearby sources of magnetic field e g NMR or other laboratory magnets before attempting to install or remove the linear motor transport as explained in Section 1 4 1 The VSM linear motor transport Figure 2 6 moves the sample You will mount the linear motor transport directly on top of the sample chamber opening after you have inserted the sample tube into the sample chamber Before you install the linear motor transport you must remove the shipping plug and install the extender tube flange assembly See Chapter 5 for more information on the linear motor tra
57. ation eee sample location 10 Position Figure 7 2 Centering scan data taken in 1 tesla applied field for the sample used in this investigation left as well as an ideal sample right Blue bar shows position shift expected when cooling from 300 K to 2 K without performing touchdowns An example of the artifact in the reported moment is shown in Figure 7 3 where the sample thermometer has reached a plateau near 10 K during cooling and hence the touchdown centering operations occur less frequently That is they occur only at 10 min intervals instead of the 1 5 min intervals which corresponded to 10 K changes at higher temperatures However it can be seen from the Center Position vs time plot that the sample chamber is still contracting at the same rate despite the fact that the VSM sample thermometer has reached a stable temperature This means that the sample walks off by as much as 0 6mm over the course of 10 minutes and the reported moment drifts accordingly Quantum Design VSM Option User s Manual 1096 100 Rev BO 7 5 February 2011 Section 7 4 Chapter 7 Sample Centering and Temperature Dependent Troubleshooting Magnetization Measurements powder cap chamber equil dat 2 PPE powder caps pressed together gap 0 Temperature K 13 0 12 8 12 6 12 4 12 2 12 0 E E E E i o a c 11 8 11 6 0 00011 0 00012 0 00013 0 00014 hattin 45 50 86 Time Stamp minutes relative Fig
58. bar o Select VSM Status Log to view the events in the VSM log since the option was activated The file located in VSM Logfiles VSMlog txt contains the entire history of this log and is a useful resource for troubleshooting o Select VSM Error Count to open a dialog showing only errors encountered as well as the total count PPS Multi u Simulation Mode File View Sample Sequence Measure Graph Instrument Utilities Help Dimer Pele a wiw el v Sequence Control VSM Status Log SM Error Count Figure 6 3 The MultiVu window and the View dropdown menu showing VSM immediate mode commands 6 3 2 Sample You can use the Sample dropdown menu at the top of the MultiVu window Figure 6 4 to install and remove samples and to center the sample manually M PPMs MultiVu Simulation Mode Figure 6 4 The MultiVu window and the Sample dropdown menu showing VSM immediate mode commands Important The Sample dropdown menu contains two install selections Install and VSM Install Remove You should always select VSM Install Remove when using the VSM The Install selection applies to the base system and is not appropriate for the VSM option Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 3 February 2011 Section 6 3 Chapter 6 VSM Dropdown Menus VSM Software o To install a sample designate an output data file and center the sample select Sample gt gt VSM Install Remove This selection
59. be head JB 3 Preamp connector on Model CM B VSM detection module lm ON ERN 9 27 OO 131211109 87654321 ff V A al Ceo 010 le OOOOOOOOOOOOO A Ra OOOOOOOOOOOO BOTTOM VIEW SAMPLE GRAY LEMO JB 3 PREAMP FUNCTION PUCK CONNECTOR ON CM B VSM AT PROBE HEAD MODULE 3 3 5 Thermometer Current 4 4 18 Thermometer Current 5 5 6 Thermometer Voltage 6 6 19 Thermometer Voltage 11 11 10 Channel 1 Input 12 12 23 Channel 1 Input 13 13 12 Channel 2 Input 14 14 25 Channel 2 Input 5 2 4 Sample Tube You will insert the sample tube Figure 5 5 into the sample chamber after you have installed the coilset puck The sample tube provides low friction guide sleeves for the sample rod The top of the sample tube consists of an integrated O ring attached to a stabilizer post The stabilizer post provides a rigid bayonet style mount that prevents the linear motor transport from tipping over Part of the post extends into the sample chamber and part extends into the extender tube flange on the bottom of the linear motor transport as shown in Figure 2 7 CAUTION You should always use the flange clamp to hold the linear motor transport onto the post even though the stabilizer post helps prevent the linear motor transport from tipping over Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 5 February 2011 Section 5 2 Chapter 5 VSM Hardware Com
60. bing with a cobalt hardened gold plating finish The adapter is made of glass filled polycarbonate which should never be exposed to organic solvents especially acetone After the assembly is fit together the added epoxy is allowed to cure straight in a fixture In the case of PPMS and VersaLab platforms brass trough holders come in a small or large diameter which fit samples of diameter in the range of 4 or 6mm respectively 1 The palladium standard pictured is mounted with GE 7031 varnish to help withstand thermal cycles during installation tests The only function is calibration of magnetometer at 1 Tesla and 298 K To get the expected moment simply multiply the mass of palladium the applied field and the susceptibility which is 5 25x10 emu gram Tesla at 298 K The expected moment at 1 Tesla for a 0 25 gram cylindrical shape is 0 013 emu While magnetization versus temperature for palladium has characteristic features it is not a suitable thermal reference standard Consider temperature independent diamagnetic Quantalloy or the Curie Weiss paramagnet dysprosium oxide pellet Even at the lowest temperatures the contribution from impurities in the varnish is below 0 196 of the large Pd moment 2 For films parallel to field the best technique for lowest background is to simply press fit with tension so the film acts as the point source dipole Contamination of the inner walls of the trough is more likely through scratches Adding glue or
61. ce so that it can perform touchdown operations See Chapters 1 and 4 for more details about touchdown operations 5 5 VSM Electronics 5 5 1 Preamp Cable Assembly Figure 5 9 shows the preamp cable assembly 3096 300 which is the electrical connection between the coilset puck and the PREAMP port JB 3 on the Model CM B detection module Integrated into the cable are dual 40 gain preamplifiers for up to two independent detection coils The preamp end of the cable is plugged into the gray connector at the PPMS probe head Figure 5 9 Preamp cable assembly 3096 300 5 8 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 5 Section 5 5 VSM Hardware VSM Electronics 5 5 2 Motor Drive Cable Figure 5 10 shows the VSM motor drive cable 3096 200 which connects the back of the linear motor transport to the SERVO port JA 1 on the Model CM A motor module The drive cable provides drive coil power to the linear motor transport position encoder read back to the module and serial communication between the linear motor transport and the module for diagnostic and configuration purposes Figure 5 10 Motor drive cable 3096 200 5 5 3 Model CM A VSM Motor Module Figure 5 11 shows the Model CM A VSM motor module 4101 100 which provides all the power and logic that are necessary to drive the VSM linear motor transport All configuration and control of this module is through
62. ces of magnetic field e g NMR or other laboratory magnets before attempting to install or remove the linear motor transport as explained in Section 1 4 1 You do not need to remove the VSM linear motor transport and its associated hardware from the system while it is idle However if you intend to use it for other types of measurements e g Heat Capacity Thermal Transport you must first remove the VSM option As summarized below you will use the VSM Install Remove Sample Wizard to prepare the system so that you can remove the linear motor transport sample tube and coilset puck These procedures are essentially the reverse of the installation procedure Summary of VSM Removal Procedures 1 Prepare for removal of the VSM transport and hardware a Set the field to zero b Use the VSM Install Remove Sample Wizard to warm the sample chamber to 300 K vent the chamber and move the transport to the load position c Remove the sample rod d Shut down the linear motor transport 2 Deactivate the VSM software application 3 Remove the linear motor transport and place it in the storage case 4 Remove the sample tube and the coilset puck 2 3 1 Prepare for Removal 1 Ifnecessary activate the VSM software from MultiVu select Utilities gt gt Activate Option gt gt VSM as explained in Section 2 2 7 e Ifthe field is not zero set it to e Use the VSM Install Remove Sample Wizard to remove the sample ro
63. chdown current VSM Adv Measure command operation to center sample in coilset During the pause the program performs a centering operation and adjusts the center of oscillation for the measurement Then it resumes the measure command continuing from the point where it stopped This operation takes about 20 seconds Cancel Help Figure 6 18 Sequence mode VSM Center Sample command VSM Center Sample Sequence popup The Center Sample sequence command is invaluable when you have disabled automatic centering by selecting No Automatic Centering but it is also useful when automatic centering has been enabled In the latter case you can place the Center Sample command in your sequence just before measurements that you would like to have performed without the interruption of a touchdown operation The measurement is still subject to the other parameters e g Averaging Time and Logging Interval that you have set but by explicitly executing the Center Sample command you reset the beginning of the interval 6 8 Sequence Mode VSM Moment vs Field Command The sequence mode VSM Moment vs Field command facilitates using sequences to make common VSM measurements such as hysteresis loops This command allows you to rapidly set the VSM to take data while sweeping the field in a variety of different patterns and it gives you the ability to control the spacing of the data points e g uniform spacing in Log Field 6 12 VSM Option
64. clamp to hold the linear motor transport onto the stabilizer post Quantum Design VSM Option User s Manual 1096 100 Rev BO 2 7 February 2011 Section 2 2 Chapter 2 1BInitial Installation of the Hardware and Software Installing and Removing the VSM Option CABLE PORT STABILIZER POST FLANGE CLAMP PREAMP PORT Figure 2 7 Installing the VSM linear motor transport on the top flange 2 2 6 Complete the System Connections Using Figure 2 8 for guidance complete the electrical connections for the VSM option After you have attached the connectors verify that the connections are firm 3100 024 CAN CABLE 4056 400 SM TRANSPORT 4101 100 MODEL CM A MOTOR MODULE 4101 150 MODEL CM B YSW MODULE FRONT PANEL 3096 200 MOTOR DRIVE CABLE 3096 300 PREAMP CABLE Figure 2 8 VSM option connections on a PPMS 2 8 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 2 Installing and Removing the VSM Option 2 2 7 Section 2 2 1BInitial Installation of the Hardware and Software Install the VSM Software Use the following instructions to install the MultiVu and VSM software applications on your PC If you purchased the VSM option as part of a new system you can go to Step 3 below Verify that the VSM software is properly installed See Chapter 6 for more information on the VSM application 1 Install the most recent version o
65. cles per measurement frequency as calculated Frequency Hz frequency of sample oscillation Peak amplitude mm peak amplitude A of oscillation such that position z t Asinot Center position mm Average position of the transport for the current data point Position is reported in motor coordinates and does not reflect the sample offset position that is shown in the locate dialog Coil signal mV uses known phasors for preamp and board to back out the actual voltage signal registered at the coilset in phase with the sample motion does not correct for the image effect Coil signal mV quadrature component of above quantity Range mV VSM board range setting this can be 0 25 2 5 25 or 250 mV 6 24 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software Section 6 10 VSM Data Files COLUMN HEADER TERM M quad signal uu DEFINITION lock in quadrature component of Moment uu field M raw emu moment with no temperature dependent correction image effect or coil shrinkage applied M raw emu quadrature component of above quantity Min temperature K minimum temperature reading of the coil thermometer for this measurement Max temperature K maximum temperature reading of the coil thermometer for this measurement Min field Oe minimum field reading of t
66. components of the VSM option VSM Hardware Components This section describes each of the basic hardware components that make up the VSM system For instructions about installing the various components please refer to Chapter 2 Linear Transport The VSM linear transport 4096 400 is the motor that moves the sample The linear motor transport and many of its component parts are illustrated in Figure 5 1 You will mount the linear motor transport directly on top of the PPMS sample chamber opening after you have inserted the sample tube into the sample chamber The sample rod is inserted into the sample chamber through an access port on top of the VSM linear motor transport The sample chamber is sealed for storage and during operations by a cap and an O ring seal An electrical connector at the rear of the linear motor transport provides the Model CM A with electrical access to the drive coil position encoder and linear motor transport calibration ROM via the motor drive cable 3096 200 or 3096 201 The sample rod is held in place in the VSM linear motor transport by a magnetic locking mechanism consisting of small magnets in the top of the rod the magnets stick to a thin steel ring at the top of the armature A spring suspension mechanism inside the linear motor transport isolates the vertical motion of the motor from the housing during vibration The resonant frequency of the spring suspension mechanism is about 5 Hz You can verify whe
67. ction 7 4 Troubleshooting Sample Centering and Temperature Dependent Magnetization Measurements 7 4 Sample Centering and Temperature Dependent Magnetization Measurements VSM Application Note 1096 305 Symptoms e inaccurate moment at low temperatures e steps in M T e low temperature M H hysteresis loops that do not close When making VSM measurements in the PPMS family of instruments PPMS DynaCool or VersaLab the sample is positioned in the detection coil set by suspending it from a carbon fiber sample rod which is held in the VSM motor The coil set is plugged into the sample chamber which in the PPMS and DynaCool is an 87 cm long sealed thin walled metal tube of which the upper 75 cm are type 304 stainless steel and the lower 12 cm are high purity copper In the case of the shorter VersaLab chamber the upper stainless section is only 17 cm long This shorter chamber as well as the reduced temperature range 50 400 K in VersaLab will reduce the effects discussed here thus this application note will focus on the PPMS and DynaCool platforms The VSM motor position is fixed at the top of the sample chamber Thus the centering of the VSM sample will be affected by relative length changes in the sample chamber versus the VSM sample rod The carbon fiber of the sample rod has a very low thermal expansion coefficient while the stainless steel of the PPMS and DynaCool sample chamber will contract in length by 2mm when the sample region t
68. d CAUTION Verify that you have removed the sample rod before continuing 2 To continue with the VSM removal process end the VSM Install Remove Sample Wizard by clicking on the Cancel button This button will close the install dialog and return you to the VSM Control Center and the Install tab Before you can remove the linear motor transport you must deactivate the VSM option as is explained in Section 2 3 2 2 12 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 2 Section 2 3 Installing and Removing the VSM Option Removing the VSM Option 2 3 2 Deactivate the VSM Option 1 Select Utilities gt gt Activate Option from the dropdown menu of the MultiVu window Figure 2 9 When the Option Manager dialog opens select VSM and click on the Deactivate button This will move the VSM option from the Active Options section of the dialog to the Available Options section The VSM Control Center and the VSM Log window will close but the MultiVu software application will remain open Continue with the VSM removal procedures below 2 3 3 Remove the VSM Linear Motor Transport l Unplug the electrical connector from the back of the VSM linear motor transport You can leave the other end of the cable connected to the Motor Module Important Never attempt to move the linear motor transport when it has a cable connected to it Remove the flange clamp from the top flange of the sample chamb
69. d length of quartz paddle with no pressure on adapter junction A thin wooden flat can transport solvent under the chip Wait for solvent to penetrate Free the sample with appropriate leverage 2 For single crystal samples and low temperature analysis put GE 7031 on crystal then secure to quartz A small amount of fine powder can be mixed into a drop of varnish although it is difficult to get a quantitative mass with this technique If taken to 340 K to cure before completely dry a large field like 5 Tesla should result in the alignment along a preferred crystallographic axis which is frozen in place by going cold Kapton tape is also effective way to secure small amounts of material but keep sample as point source and tape symmetrical along the axis of motion Concern with tape is the random contamination from dust in a lab environment 3 To clean the quartz paddle use a solvent specific to the glue Cotton swabs help keep all solvents away from the polycarbonate adapter especially acetone Do not use sonicator which could introduce cracks at the junction points The common break point is at the adapter junction and caused by lateral force on the sample rod Frequently breakage occurs during the sample mounting and cleaning process 3 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 3 Section 3 3 Sample Preparation and Mounting 2BMounting Samples B The brass trough is made from cartridge brass tu
70. dvanced tab of the VSM Measurement dialog Figure 6 16 contains settings for Excitation Parameters Ranging and PPMS Data Logging Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 9 February 2011 Section 6 4 Chapter 6 VSM Control Center VSM Software 15 xl Settings Centering Advanced m Last Measurement Excitation Parameters Temperature 11 9 K Peak Ro m Frequency u Max Accel 125331 m sec m e Rangng C dcus NEZ PPMS Data Logging Select Field 140000 0 Oe Figure 6 16 Advanced tab in the VSM Measurement dialog Excitation Parameters The excitation parameters are explained by the equation Position time Peak Amplitude x sin 2n Frequency xtime o The Peak Amplitude is typically set to 2 mm and can be varied from 0 1 to 5 mm with a recommended range of 0 5 to 4 mm Low amplitudes allow for measuring a larger moment see Max Moment value in this dialog because the induced coil set signal is proportional to the amplitude However low amplitudes 0 5mm can result in an inaccurate reported moment High amplitudes provide more coil set signal but also produce large accelerations see Max Accel value in this dialog which can lead to higher noise in measurements Important Quantum Design staff recommend that you limit the maximum Peak Amplitude to 4 mm because the motor module could overheat at greater amplitudes By limiting the maximum Peak Amplitude to
71. e In the event you attempt to use commands in the Measure dropdown menu but you have not installed a sample a popup message will open directing you to first install a sample MN PPMs MultiVu Simulation Mode File View Sample Sequence Measure Graph Instrument Utilities Help E bi fe B a E VSM Measure Dlejkl eje Eal VSM Center Sample VSM Datafile Comment Figure 6 6 VSM immediate mode commands in the context of the MultiVu window and the Measure dropdown menu o To set up and take measurements select Measure gt gt VSM Measure The VSM Measurement dialog will open Figure 6 14 with three tabs or pages of settings you can use to delineate your measurements The same dialog appears when you click on the Measure button in the VSM Control Center For a complete explanation of the VSM Measurement dialog see Section 6 4 2 6 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software 6 4 Section 6 4 VSM Control Center o Tocenter a sample select Measure gt gt VSM Center Sample This selection sequence opens the VSM Center Sample popup Figure 6 7 which allows you to initiate touchdowns at will As explained in Chapter 4 centering operations help ensure the accuracy of measurements o To add a comment to a VSM data file select Measure gt gt VSM Datafile Comment When the VSM Datafile Comment popup appears Figure 6 8 enter your comment in the tex
72. e Features of the VSM System eee cesceeeceseceseeeseeeeaeesaeesaeecaaecaecsaeenseeseeeeaes 1 1 1 3 Theory ot Opefatlon treten etre Eee ee ech his devel te eer t eei PE tee Mise 1 2 1 4 Safety Precautiors 5 re tie getto nee eee ie ete rece Ee eri roots 1 4 1 4 T Magnets inuicem tetti ce eee oett P E RE s e Ee posts 1 4 14 2 Cry OPENS cia o te ute tette emet cute nds 1 5 1 4 3 Electricity 3 eee het edere tbe e e n m e bsec EE E RE ie 1 6 144 JIat ns and Handle iunii d eee eR er Oe ee Re i dete 1 6 LS Contacting Quantum Design eei pee tie eee dere el pesi Fea PEL oS PEL aida 1 6 CHAPTER 2 Installing and Removing the VSM Option eee ecce eese eee eee enne seen sese en sese ta se enuo 2 1 QA Introduction o ehe emeret eerte teet reete dete TT eee eee ee Meer Ep RE eoe 2 1 2 2 Initial Installation of the Hardware and Software sees 2 1 2 2 1 Install the Modular Control System and CAN Network Adapter PPMS ONLY 2 3 2 2 2 Prepare the system for Option Installation eese 2 4 2 2 3 Jnstallthe Coilset Puck decedat Oe OE Ear ERES 2 4 2 2 4 Insert the Sample Tube uen Re Se re ee pee ERU seals 2 5 2 2 5 Mount the VSM Linear Motor Transport sees nennen 2 6 2 2 0 Complete the System Connections essere nennen nennen enne 2 8 2 2 7 InStall the VS M SO UWAre esee er ertt e bee ets e eee e E M RR PEE Deko cde 2 0
73. e and is outlined in Section 4 3 3 o Configure VSM System will allow the user to select a different active VSM coilset see Section 2 2 8 Coilsets are distinguished by serialization on the puck base see Section 5 2 3 and there is a corresponding calibration file VSMxxx CFG in the VSM Calibration folder One sign that an incorrect coilset is in use is that the temperature between coilset and base system differ by gt 1 or the VSM option declares that the option thermometer is not responding 6 4 1 2 DATA FILE TAB The Data File tab Figure 6 10 identifies the output data file that will contain the measurement data If you have not selected an output data file the File Name and Title panels in the Data File tab will be blank View Button The View button opens the graph view of the active output data file To use the View button you must have designated an output data file Browse Button SM SIM No Datafile o x The Browse button initiates a series of Install dialogs that guide you through the process of Path designating selecting or creating a data file C QdRpms D ata ample Advanced The file designation process and the dialogs File Name are similar to the ones in the Install Remove Sample Wizard see Section 4 3 3 Title nn Important You must designate an output data file by selecting an old file or by making Browse view a new one if you want the measurement data saved If no da
74. e tsi t e te Leere dta 4 1 4 2 Overview of VSM Measurements cessere nennen nnne tenente enne enne en 4 1 4 2 b Sample Centering aoro citet Pre tete PE Re ee etd bride 4 1 4 2 1 1 The Touchdown Operation sese ennemi 4 2 4 2 1 2 Scheduling Touchdown Operations eene ene 4 2 4 2 0 VSM Measurement Process Synchronous Detection eesseeeeeeenene 4 2 4 3 JInstallimp a Sample aet hae eerte er ib tete gp etd feni eels 4 3 4 3 1 Attach a Sample and Measure the Sample Offset sse 4 3 4 3 2 Activate the VSM Option and Control Center esee 4 4 4 3 3 stall the Sample itt nte tbe i e ee PR HS tal ce ba Meese 4 4 4 4 Taking Immediate Mode VSM Measurement eeeeseeseeeneeeeeenee eene ren rennen 4 6 4 4 1 Measure Command and VSM Measurement Dialog eee 4 6 CHAPTER 5 VSM TRA WAL uostri toe neta eraot on Ei e Nasa reo eau ve v tot epot vn ea I re esa rt eui 5 1 Soll AIntroductiOn ee e e e las ee edt ie etie Pte he ete to d Gan tee deed 5 1 5 2 VSM Hardware Components idee redet eL ute te deti secto eee eset ied ida 5 1 224 Lanear Transport eet p ete da p e ie tiep eui 5 1 5 2 2 Storage Case for Linear Motor Transport ener 5 3 2 2 3 Collset PUCK nionem de desmteaeenadeutd ami 5 3 5 24 Sample TUD i uet e Ee Ue Eten ertt a e ene EET e Deo 5 5 23 2 5 o Sample Rod oui eee ede tee Ge Heine eee teta ce
75. e when you have selected the Continuous Measurement option which can generate large volumes of data Use the Keep options to choose the percentage of data points that will be written to the data file See the Estimated explanation below for more on the issue of file size Temperature Controt Start 300 K End 13 K Sweep Rate 1 K min Stabilize at each Temperature Sweep Continuously r Data Acquisition 1 Continuous Measuring m Averaging Time c Num Repetitions at each 1 Temperature Keep J all measurements bd all measurements 50 of measurements 20 of measurements 10 of measurements 5 of measurements 2 of measurements 1 of measurements F al a Time 02 30 h m Estimated _ E 217887 Figure 6 32 Data Acquisition section Keep Approximate Temperature and Estimated settings VSM Option User s Manual 1096 100 Rev BO February 2011 6 21 Section 6 9 Chapter 6 Sequence Mode VSM Moment vs Temp Command VSM Software 6 9 2 3 APPROX TEMPERATURES The Approx Temperatures list Figure 6 32 displays in sequence a close estimate of the temperatures at which the VSM will take data These temperatures are based on all your selections in the Temperature Control and Data Acquisition sections of the Setup tab 6 9 2 4 ESTIMATED The Estimated area Figure 6 32 displays the estimated amount of time in
76. eceives network data and receives power A 4 1 Address Selector Each module on the CAN bus must have a unique 5 bit binary address The selector on the back panel is used to set the four least significant bits and an internal jumper sets the most significant bit If the selector is set to zero 0 the module uses its default address For a Model CM A VSM motor module the default address is 10 or equivalently A on the selector A 4 2 Single Guide Hole The single guide hole is used to align the connector with one of the back row high power receptacles on the Model 1000 modular control system Figure A 6 Rear panel of the Model CM A VSM motor module Quantum Design VSM Option User s Manual 1096 100 Rev BO A 7 February 2011 Section A 5 Maintenance A 4 3 A 5 A 8 Appendix A Model CM A VSM Motor Module QD CAN Connector The QD CAN connector is the main communication connection for controlling the module The CAN network signals CAN High CAN Low are connected to all other CAN modules on the bus and to the PC Power 24 volts reset and sync signals are also provided to the module though this connector OOOQOQO OOOQOD Figure A 7 Quantum Design CAN connector for the Model CM A VSM motor module Table A 6 QD CAN connector on the rear of the Model CM A VSM motor module PIN FUNCTION 24 V CAN Low
77. ection module B 2 JB 1 Motor sync connector for the Model CM B VSM detection module B 4 JB 3 Preamp connector for the Model CM B VSM detection module B 5 Rear panel of the Model CM B VSM detection module sees B 6 QD CAN connector on the rear of the Model CM B VSM detection module B 7 VSM Option User s Manual 1096 100 Rev BO February 2011 Quantum Design Tables Table 2 1 Table 3 1 Table 3 2 Table 5 1 Table 6 1 Table A 1 Table A 2 Table A 3 Table A 4 Table A 5 Table A 6 Table B 1 Table B 2 Table B 3 Table B 4 Table B 5 Quantum Design Contents Table of Tables VSM system componieris dere e PREIS SPESE RELEASE PRENSA E RR EPA E ES 2 2 Calculated ratio of the reported moment to the true moment for different size cylindrical samples and different amplitudes sess 3 2 Calculated ratio of the reported moment to the true moment of cylindrical samples for different radial offsets from the coilset centerline 3 3 Sample Connection with VSM Detection Cable Connected sss 5 5 Definitions of column headers for VSM data files dat files as shown in the order DITS AED 6 24 Electrical specifications for Model CM A VSM motor module A 3 LED guide for Model CM A VSM motor module eee A 3 JA 1 Servo co
78. ed 4 2 2 VSM Measurement Process Synchronous Detection To perform VSM measurements the Model CM A VSM motor module is programmed to oscillate the sample at the center of the coilset at a predetermined frequency and amplitude The voltage induced in the coilset is then amplified by the preamp and detected by the Model CM B 4 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 4 Section 4 3 Taking VSM Measurements Installing a Sample VSM detection module The VSM detection module also reads the real time sample position from the motor module The VSM detection module uses both the position and voltage signals to generate a complete and independent magnetization measurement every cycle of oscillation In principle a 40 Hz oscillation frequency can produce a 40 Hz data rate from the module These data are averaged over an amount of time that you specify For example if you specify an averaging time of second and the oscillation frequency is 40 Hz the detection module would average the 40 readings per second into one reading per second To obtain an accurate measurement of the magnetic moment the VSM software application uses calibration data from calibration files on the PC and from ROMs in the modules The calibration data includes corrections for preamplifier gain errors phase shift errors and the geometry of the coilset puck 4 3 Installing a Sample 4 3 1 Attach a Sample and Measure the Samp
79. ed network connection to the computer PC See the Model 1000 Modular Control System User s Manual for more information about the Model 1000 modular control system Figure 5 13 Model 1000 modular control system 4100 001 5 10 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 5 Section 5 5 VSM Hardware VSM Electronics 5 5 6 CAN Computer Interface Kit The CAN computer interface or network adapter kit contains the CAN based network adapter cable 3100 024 and software that are needed to connect the Model 1000 to the computer PC For measurement platforms such as DynaCool and VersaLab the CAN Computer Interface is built into the instrument Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 11 February 2011 C HAPTER 6 VSM Software 6 1 Introduction This chapter contains the following information o Section 6 2 describes option activation and deactivation Section 6 3 describes the VSM specific dialogs and menu items in the MultiVu dropdown menus Section 6 4 describes the VSM Control Center and its components Section 6 5 briefly describes sequence mode commands Section 6 6 explains use of the VSM sequence mode Adv Measure command Section 6 7 explains use of the VSM sequence mode Center Sample command Section 6 8 explains use of the VSM sequence mode Moment vs Field command Section 6 9 explains use of the VSM sequence mode Moment
80. elds where the VSM will take data points based on all your selections in the Field Sequence Field Control and Data Acquisition sections of the Setup tab 6 8 2 5 ESTIMATED The Estimated area Figure 6 26 displays the estimated amount of time in hours and minutes that will be needed to complete the measurement as well as the estimated number of lines in the output data file The estimated number of lines in the output data file is also the total number of data points generated by your measurement 6 8 3 Sequence Mode VSM Moment versus Field Dialog Advanced Tab The Advanced tab Figure 6 20 organizes the settings for measurement details e g the VSM measurement parameters and the field approach mode and has options that control how the VSM takes measurement data Experienced users will notice that the Centering Ranging Data Logging and Excitation Parameters subsections of this tab are identical in form and function to sections of the VSM Measurement dialog 6 8 3 1 CENTERING SETTINGS Use the Centering section of the Advanced tab to set the conditions for the VSM to perform touchdown operations For more information on Centering see Section 6 4 2 4 6 8 3 2 RANGING SETTINGS Use the Ranging section of the Advanced tab to set the way the system chooses the gain of the amplifiers in the VSM module during measurement For more information on Ranging see Section 6 4 2 5 6 8 3 3 PPMS DATA LOGGING SETTINGS The Select but
81. elow VSM Option User s Manual 1096 100 Rev BO 6 13 February 2011 Section 6 8 Chapter 6 Sequence Mode VSM Moment vs Field Command VSM Software 6 8 2 4 FIELD SEQUENCE SETTINGS Use the options in the Field Sequence section Figures 6 21 and 6 22 to set the amplitude and order of the field changes during the Moment vs Field measurement Field Sequence Field Sequence Select Start End Quadrant Select Start End Quadrant Hmax 5000 Hmax Ho AAN 4 NN Hmi time 5000 Hmin time Click and drag to choose start and end fields Oe Click and drag to choose start and end fields 5000 800 De Figure 6 21 Field Sequence section of the VSM Moment Figure 6 22 Field Sequence section of the VSM vs Field Setup tab Start End Quadrant de selected Moment vs Field Setup tab Start End Quadrant selected o Hymax defines the maximum field used in the measurement o Ho defines a starting or ending field used in the measurement By default Ho is the starting point of the measurement but you also can use Hmax or Hmin as the starting point o Hin defines the minimum field used in the measurement Note Uniform spacing is referenced between Hmax and Hmin This can affect whether Ho is used in the measurement as is explained below in the Data Acquisition subsection o Select Start End Quadrant Figures 6 21 and 6 22 allows you to use your mouse to set the starting and ending fields of the measurement To set the startin
82. emperature changes from 300 K to 2 K The VSM software provides a sample centering mechanism which is referred to as the touchdown operation and compensates for this relative shift by periodically touching the end of the sample holder down to the VSM detection coil set base so that the current position of the sample relative to the coil set is determined see the relevant VSM Option User Manual for your platform for more details on this Figure 7 1 shows a VSM data file for a moment vs temperature sweep in which touchdown sample centering was performed every 10 K or 10 minutes these are the default settings The Center Position mm quantity refers to the motor s position where 65 mm is the top of travel and 0 mm is the bottom thus any changes to this value will reflect relative length changes between the sample rod and sample chamber An increase in the center position value means that the sample chamber has contracted relative to the sample rod This temperature scan was done very fast 7 5 K min in order to demonstrate the effect of thermal contraction note the logarithmic axis for temperature The main point in this figure is that the sample position is moving for 4 hours after temperature is stabilized at the VSM coil set This 1s because of the large thermal mass of the middle portion of the stainless steel tube and the fact that the temperature control algorithm is optimized in order to stabilize the temperature at the sa
83. eory of operation and gives contact information for Quantum Design service representatives o Chapter 2 describes VSM installation and removal procedures o Chapter 3 covers sample preparation and mounting for measurement with the VSM o Chapter 4 summarizes the VSM measurement process and guides you through an immediate mode measurement with the VSM option o Chapter 5 describes the hardware and electrical components of the VSM option as well as the VSM User s Kit o Chapter 6 describes the VSM application software and the use of immediate mode and sequence mode commands to take measurements Quantum Design VSM Option User s Manual 1096 100 Rev BO XV February 2011 Section P 4 Preface Conventions in the Manual Contents and Conventions o Chapter 7 describes some troubleshooting strategies for VSM measurements o Appendix A provides a functional description of the Model CM A VSM motor module including diagrams and electrical specifications o Appendix B provides a functional description of the Model CM B VSM detection module including diagrams and electrical specifications o Appendix C lists Applications and Service Notes pertaining to the VSM Option and provides a place for the user to include new technical notes P 4 Conventions in the Manual File menu Bold text identifies the names of menus dialogs options buttons and panels used in the PPMS MultiVu and VSM software File gt gt Open The gt gt symbol indicates
84. er see Figure 2 7 Slowly lift the linear motor transport until it has cleared the stabilizer post see Figure 2 7 Place the linear motor transport back in the storage case 4096 150 WARNING Store the VSM linear motor transport in a secure location to prevent it from being attracted to magnetic fields in the laboratory including those produced by the superconducting magnet as explained in Section 1 4 1 2 3 4 Remove the VSM Sample Tube and Coilset Puck l 2 3 Remove the VSM sample tube from the sample chamber Remove the VSM coilset puck from the sample chamber by using the puck extraction tool Unplug the VSM preamp cable from the probe head and set it aside You do not need to disconnect the other end of the cable from the Motor Module Return the blank flange to the top of the probe head or install another of the Quantum Design measurement options When the sample chamber has been closed you can purge and seal it by using the Chamber dialog box e Select Instrument gt gt Chamber e Inthe Chamber dialog box click on the Purge Seal button The base measurement system is now ready for you to install a different option See Footnote 1 Quantum Design VSM Option User s Manual 1096 100 Rev BO 2 13 February 2011 C H A P T ER 3 Sample Preparation and Mounting 3 1 Introduction This chapter contains the following information o Section 3 2 discusses constraints on t
85. er field magnets e g 7 T 9 T After repeated insertions of the VSM puck the contact fingers at the base of the coilset above the serial number in Figure 5 3 might bend inwards which would loosen the fit of the coilset in the bottom of the sample chamber When this happens you should make the coilset fit snugly again by using the puck adjustment tool as described in the Physical Property Measurement System Hardware Manual Chapter 5 VSM Hardware MOUNTING RING FOR PUCK INSERTION TOOL COILSET SERIAL ER REQUIRED jY SOFTWARE Figure 5 3 Coilset puck 4096 204 ER d eM 4 p T hi O D INE P PICKUP COIL d i E S a COUNTER WOUND IN PICKUP COILS H _ SAMPLE BORE PUCK SURFACE D VUA Figure 5 4 The internal dimensions of a standard coilset puck are as follows Bore diameter B 6 33 mm coil thickness T 1 78 mm coil spacing S 7 11 mm coil inner diameter ID 7 73 mm coil outer diameter OD 13 7 mm height above puck surface H 40 1 mm 5 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 5 Section 5 2 VSM Hardware VSM Hardware Components Table 5 1 Sample Connection with VSM Detection Cable Connected Note that pins 7 10 on the sample puck are unused Also the detection coilset is connected to Channel 1 puck pins 11 and 12 sample puck pro
86. ering scan on the sample as is typically done in the sample installation wizard of the VSM software This data for the most recent scan is stored in the file SCanData dat located in the NVSMNLogFiles folder Figure 7 2 shows centering scans for the sample measured here left as well as an ideal sample right The vertical axis Source corresponds to the magnetic moment in units of emu while the horizontal axis Position is the motor position in units of mm The sample used for this investigation was two empty VSM powder sample holders pressed together and was chosen because the reported moment was a strong function of position change in reported moment vs vertical position dM dz 20 per mm When measuring small magnetic moments this often occurs because the magnetic end effect of the sample holder or other nearby material like the powder capsules can dominate over the magnetic response due to the sample In contrast the ideal sample exhibits an extremum at the sample location so that the moment is independent of position to a first order approximation in older versions of VSM software one must plot M R instead of Source on the vertical axis 7 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 7 Section 7 4 Troubleshooting Sample Centering and Temperature Dependent Magnetization Measurements BS scondatedar EMRE NEGET DE slope 0 slope 20 per mm thermal contraction 2mm sample loc
87. ernal tin process Nb3Sn magnets Remanence is the field that remains in the magnet after it has been brought back to zero current from full field Flux jumping is not a problem in the low field magnets up to 9 T because the windings are made of NbTi superconducting wire which does not pin flux as strongly as the Nb3Sn wire and which has not been found to present a problem for VSM measurements while ramping the field Additionally the remanence in these magnets is generally less than about 10 Oe at the sample location Figure 7 6 illustrates flux jumps and their effects on moment versus field data collected with a 14 T magnet during ramping and stable fields The data show flux jump noise in the magnetic moment while the field is ramping but the noise has settled by the beginning of the field iteration phase Thus by the time that field stability has been declared labeled Holding in Figure 1 the flux jumps have clearly subsided Note that the driven mode was used for the measurements presented in Figure 7 6 pps Multi u Driven dat Simulation Mode Driven dat E y E nj x amp File View Sample Sequence Measure Graph Instrument Utilities Window Help m B x aleja e em gt e S u amp Moment emu flux jumps g i H ramping Iterating Holding PPMS Status code Time Stamp seconds relative Figure 7 6 The effect of flux jumps on VSM moment versus field data during ramping
88. ert sample holder and aligned rod into VSM at 300 K and nearest zero field Use wizard to manually locate the sample position as previously measured e Run exact sequence to be performed when the sample is present The sensitivity and precision of the VSM style lock in technique allows accurate background determination even though a center response function may not be obtainable e After sequence complete remove parts from brass trough Weigh both pieces put powder inside the opening of one and securely close with the remaining piece Weigh mass of assembly in addition to keeping track of mass change in source e Secure in brass trough and accurately measure location of gap using mounting station e At first use wizard to manually locate sample position Once field is applied perform centering function Repeat sequence run with the blank holder e The use of standard materials of similar dimensions and signal should be run for verification of the accuracy of the process We have shown that remarkably sensitive measurements are easily obtained especially for low field magnetization versus temperature analysis A video of this process is available from Quantum Design Please e mail request to applications qdusa com 5 The epoxy curing of powder into pellet pictured on left is used for AC Susceptibility standard of Dysprosium Oxide Dy O Start by weighing sample mass and mixing both parts of the epoxy Add smallest amount of thin
89. ese dialogs are similar to the ones used to set up the immediate mode measurements Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 11 February 2011 Section 6 8 Chapter 6 Sequence Mode VSM Moment vs Field Command VSM Software 6 6 Sequence Mode VSM Adv Measure Command When you select and click on the sequence mode Adv Measure advanced measure command the sequence mode VSM Measurement dialog opens so that you can specify the measurement parameters These dialogs mirror those of the immediate mode measurements described above so they will not be repeated here 6 7 Sequence Mode VSM Center Sample Command If you choose not to use automatic centering you will need to perform centering operations by using the dropdown menu or by inserting centering operations into a sequence file As explained in Chapter 4 centering operations help ensure the accuracy of measurements keeping the centering position stable to within about 0 1 mm at the center of the pickup coils by informing the system about sample position shifts with respect to the coilset To insert a centering operation into a sequence file click on the Center Sample sequence command in the Sequence Commands bar This opens the VSM Center Sample Sequence dialog shown in Figure 6 18 When the sequence file is run and the VSM Center Sample Sequen program encounters the Center Sample sequence command it temporarily halts the Press Center to perform tour
90. estions should help prevent problems due to sample mounting 1 Verify that the sample is rigidly mounted in the sample holder keeping in mind that the accelerations during VSM measurements are very high Noting that acceleration amplitude frequency then for a VSM peak amplitude of 2 mm and a frequency of 40 Hz the acceleration is as high as 126 m sec during a cycle 2 Use an adhesive to hold the sample if possible Examples of recommended low temperature adhesives are GE 7031 varnish or Devcon Duco cement These are both soluble in common laboratory solvents a toluene alcohol mixture in the case of the GE varnish and acetone in the case of the Duco cement 3 Inspect all glue joints on the sample rod and sample holder for loose connections 4 Verify that powdered samples are packed tightly so that they are immobilized 7 6 Performing VSM Measurements in PPMS High Field 14 T or Higher Magnets VSM Application Note 1096 301 Symptoms e noise in Moment when measuring during a field sweep at low fields The VSM option for the PPMS offers rapid measurements data can be collected fast greater than Hz data rate and it can be collected while the magnetic field is being ramped However when a 14 T or higher magnet is used to measure between 2 T and 2 T Quantum Design advises users to measure at stable magnetic fields The reason for this advice is that there is 7 8 VSM Option User s Manual 1096 100 Rev
91. ete OE 5 6 3 3 VSM Option User s Katz s WA Were teri ew rs 5 7 5 4 Sample Mounting Stationissa cccceccecssecesseeceeaceceeeeeeaeceeaaecseneeceeecaecseaeeceeeeeesaeceeaaecseneeees 5 8 2 29 NSM Electronics eoi Rete endete nnnm 5 8 2 91 Preamp Cable Assembly renee o eee at eter eer E AE E nee a ese paar eee tg 5 8 55 2 Motor Drive Cable tese eo Wane nib eatin eae 5 9 5 5 3 Model CM A VSM Motor Module ccccccccssssecssssceceessececesseeeeceeeneeeceseeeesseeeaeeceseeaaees 5 9 5 5 4 Model CM B VSM Detection Module sss enne enne 5 9 5 5 5 Model 1000 Modular Control System essent enne 5 10 vi VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Contents Table of Contents 5 5 0 CAN Computer Interface Kit leet eet ueieetee aeae EErEE Se desea ie rtp pede 5 11 CHAPTER 6 VSM SOW cic M 6 1 6 E Introduction cete eame aene ea 6 1 6 2 Activating and Deactivating the VSM Option cece cesecsseceseceseeeeeesseeeseesaeecsaecaecaecnaeceaeen 6 1 6 3 VSM Dropdown Menus stevie cena n ete ea ee dats Wieland adie Ie E Y ENERE 6 3 6 3 NIC WES ine tese eee Se Le ete eret tette a ei er Het 6 3 6 3 27 Sample iuste He o nU IE He doe t HERO I Heure ee DOE ise 6 3 0 3 3 Measure nie rere bee fite tet ute eerte restet uet Rete 6 4 6 4 VSM Control Centet 3 5 naut e Uc e Hei e it a P t ene 6 5 6 4 1 VSM Control Center Components
92. ets B 1 B 2 1 Functional Block Diagram s s erede terrere rte ete pe ehe etre eeren e ianao eieaa B 2 B 2 2 Specifications een Le pe Mane ee eee e et dre petebat B 3 B 3 Model CM B Detection Module Front Panel eseessesseeseeeeeeenenee enne B 3 B 3d Indicator LEDS tette RERO REN HREENU EE Te HER loa add B 3 viii VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Contents Table of Contents B 3 2 Connectors and Pinout Tables ancrer i a B 4 B 3 2 1 JB 1 Motor Sync Comnector cccicsscccsesccessassssscsostccesesssstcesesacesneaessoesooseceesssesnea B 4 B 3 2 2 JB 2 Monitor BNO denas tete tolerate oe CBS B 4 B 3 2 3 JB 3 Preamp Conn ctor eee eet Dee te e nene e eee coats B 5 B 4 Model CM B Detection Module Rear Panel nennen nnne B 6 B 4 1 Address Selector 3 eere etate eet e ee P AGE N B 6 B 4 2 GundeHolesi eee eher B 6 B 4 3 OD CAN Conector eie P Eee D e Eta Hee LEER es B 7 APPENDIX C Application and Service Notes VSM cete eee eese eene seen eese tn sese en aset ta sese ea seen se eno C 1 BG URES e n X MALE UG y c PP AE XIII Quantum Design VSM Option User s Manual 1096 100 Rev BO ix February 2011 Contents Table of Figures Figures Figure 1 1 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 Figure 2 10 Figure 2 11 Fi
93. f a problem Important The error information in Table B 2 refers to situations that persist for longer than about 15 seconds Typically when the module is powered on the LEDs briefly flash red before they turn green This is a normal part of the startup or reset sequence Table B 2 LED guide for the Model CM B VSM detection module LED COLOR STATUS MEANING AND OR SOLUTION PWR Green On The processor is running with no errors normal Red Flashing Errors were encountered during the self test The flashing sequence can be used to determine the cause of the failure COP Green On CAN status is operational normal Flashing CAN status is pre operational Verify that cable is connected to PC Red On or Error on the CAN bus Contact Quantum Design for flashing assistance If you are unable to achieve operation with both LEDs green please contact Quantum Design for assistance VSM Option User s Manual 1096 100 Rev BO B 3 February 2011 Section B 3 Appendix B 2BModel CM B Detection Module Front Panel Model CM B VSM Detection Module B 3 2 Connectors and Pinout Tables B 3 2 1 JB 1 MOTOR SYNC CONNECTOR This connector reads the motor encoder position from the Model CM A VSM motor module as a high speed digital serial signal Important This sync connector and the short crossover sync cable 3096 400 to module CM A are no longer used in newer versions of firmware
94. f the MultiVu software if it is not already installed 2 Install the VSM software by starting the VSM software setup wizard and following the instructions 3 Verify that the VSM software is properly installed by activating it from within MultiVu a Start the MultiVu application program b Goto the Utilities menu on the main MultiVu menu bar at the top of the application window c Select Utilities gt gt Activate Option Figure 2 9 PPM Multivu Simulation Mode 1nixi File View Sample Sequence Measure Graph Instrument Utilities Help Djela e e e v e e MESIEIEZZN Configure Option Log PPMS Data Upload Send GPIB Commands Magnet Error Handling Event Log Sigma Log PPMS Data Helium Fill Status Calculator EverCool Figure 2 9 PPMS MultiVu menu bar and Utilities dropdown menu with Activate Option selected 4 Three events will occur as soon as you have activated the VSM option Quantum Design The VSM Log window and the VSM Control Center will open see Figure 2 10 In the control center you will see four panels or tabs Install Data File Sample and Advanced The Install tab is usually at the front when the control center opens When running in simulation mode the VSM Control Center is titled VSM SIM Note the Configure VSM System button under the Chamber Status area of the Install panel you will use this button to verify and test the coilset calibration in the next phase
95. g and ending quadrants the area between the field set points place your mouse pointer in the diagram left click the field for the start of the measurement drag the pointer to the end field and release the left button The selected quadrants will be highlighted and included in the measurement NOTE Drag the cursor from left to right when selecting quadrants 6 8 2 2 FIELD CONTROL SETTINGS Use the settings in the Field Control section Figure EET Control 6 23 of the Setup tab to control how the magnetic field changes between the field set points Some SHEET 10 Eisen choices will be unavailable due to different magnet Driven at each field types C Persistent at each field Sweep Sweep Rate i End Mode Persistent Y The Sweep Rate value sets the rate at which the field changes when the magnet is ramping up or Figure 6 23 Field Control section of down the VSM Moment versus Field dialog Driven at each field The Driven at each field radio button sets the magnet to stabilize the field in Driven mode at each field shown in the Approximate Fields list Figures 6 19 and 6 26 Persistent at each field The Persistent at each field radio button sets the magnet to stabilize the field in Persistent mode at each field shown in the Approximate Fields list Figures 6 19 and 6 26 6 14 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 Section 6 8 VSM Software Sequence Mode
96. ground contribution The technique is appropriate for samples directly in contact with the brass or through various support mechanisms B The term glue is loosely applied to any material that will secure a sample to a support material Generally the materials will harden over time with the process aided by increasing temperature and keeping under vacuum Pockets of trapped oxygen or adsorption to very high surface area materials will produce a magnetic signature around 50 K Each material has a specific range of conditions for optimal usage with varnish best at the lowest temperatures and Duco cement the most easily removed Since the contents of each glue are not normally disclosed by manufacturers it is hard to know magnetic properties A general rule is that colorless materials are less magnetic than colored ones because dyes used in the materials tend to have magnetic signature However it is best for users to verify the magnetic property of the glue 1 The legendary GE7031 varnish is a vinyl phenolic adhesive safety labeling H 1 F 4 R 3 PE 3 As the bulk material in container ages it will become thicker Adding iso propanol IPA and or toluene will thin solution Cleaning is best aided with toluene The aging and or oxidation process will lead to a darker coloring of the solution This tends to correlate with increased magnetic signature The ideal solution is a light tan honey colored solution freely flowing without addition of extra so
97. gure 2 12 Figure 2 13 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Figure 4 5 Figure 5 1 Figure 5 2 Figure 5 3 Figure 5 4 Figure 5 5 Figure 5 6 Figure 5 7 Figure 5 8 Figure 5 9 Figure 5 10 Figure 5 11 Figure 5 12 Figure 5 13 Operating principle for the VSM option emen 1 3 System components for PPMS VSM option cee ceeeseeeeseeeseeeseeessecnsecsaecnseeeseeees 2 3 Coilset puck 4096 204 or 4096 600 with arrows to coilset serial number and to mounting ring for attaching the puck insertion tool see 2 5 Installing the VSM coilset puck with the puck insertion tool 2 5 VSM sample tube assembly 4096 301 is shown for example 2 5 Inserting the VSM sample tube into the sample chamber sess 2 5 Front and rear views of the VSM linear motor transport 4096 400 2 6 Installing the VSM linear motor transport on the top flange esse 2 8 VSM option connections on a PPMS sse eene 2 8 PPMS MultiVu menu bar and Utilities dropdown menu with Activate Option selected istinc manut ee aine enim 2 9 VSM Control Center and VSM Log window seen 2 10 PPMS MultiVu menu bar and Measure dropdown menu for VSM option 2 10 Configure VSM System dialog page 1 sse 2 11 Configure VSM System dialog page 2 Testing c
98. has subsections for Temperature Control and Data Acquisition A scroll bar at the right side automatically displays Approx Temperatures that are based on the other settings The subsections and their settings are explained below SM Moment versus Temperatuj 6 9 2 1 TEMPERATURE CONTROL SETTINGS Use the options in the Temperature Control subsection Figure 6 30 of the Moment versus Temperature dialog box to set the general parameters of a moment versus temperature measurement Quantum Design February 2011 Setup Advanced Start 300 Sweep Rate 10 r Temperature Control End fis K Stabilize at each Temperature Sweep Continuously K min Figure 6 30 Temperature Control section of the sequence mode VSM Moment versus Temperature dialog VSM Option User s Manual 1096 100 Rev BO 6 19 Section 6 9 Chapter 6 Sequence Mode VSM Moment vs Temp Command VSM Software Start and End The Start value sets the temperature in degrees Kelvin at which the measurement will start during a temperature sweep The initial temperature can be larger or smaller than the final temperature so you can collect data while the sample is being warmed or cooled The End value sets the temperature in degrees Kelvin at which the moment versus temperature measurement will end Sweep Rate The Sweep Rate value sets the rate at which the temperature changes in degrees Kelvin per mi
99. hdown Centering at Intervals is recommended in order to keep the sample close the center of the coil set e In Advanced tab Use Peak Amplitude 2mm default Frequency usually 40 Hz and Sticky Autorange Last Measurement Area The right side of each panel consists of the Last Measurement area which displays the most recent measurement results The displayed data are also written to the open data file along with the data items that are defined in the table in Chapter 6 4 6 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 4 Section 4 4 Taking VSM Measurements Taking Immediate Mode VSM Measurements VSM Measurement Settings Centering Advanced Last Measurement Measure Type Temperature 1 9 Continuous Measuring Field 160000 0 Single Measurement Moment 1 2434 Measurement Parameters Moment Std 5 76n6E 05 Averaging Error Time sec Logging Interval Sec Figure 4 5 VSM Measurement dialog Quantum Design VSM Option User s Manual 1096 100 Rev BO 4 7 February 2011 C H APTER 5 VSM Hardware 5 1 5 2 5 2 1 Introduction This chapter contains the following information o Section 5 2 describes each of the basic o Section 5 4 describes the sample mounting hardware components that make up the station and its use VSM option o Section 5 3 describes the contents of the o Section 5 5 describes the electrical VSM User s Kit
100. he coil thermometer for this measurement Max field Oe maximum field reading of the coil thermometer for this measurement Mass grams mass of transport as obtained from DC component of motor force Motor lag deg phase lag between motor drive current and motion Pressure torr pressure in sample chamber VSM status code status codes unique to the VSM module Motor status code status codes unique to the motor module Measure status code error condition codes of varying severity Zero indicates no errors Status code status code for base system System temp K block temperature System field Oe currently the same as the Magnetic Field Oe column Pressure pressure in sample chamber as reported by high vacuum gauge when present Map 25 VSM coil set temperature Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 25 February 2011 C H APTER 7 Troubleshooting 7 1 7 2 Introduction This chapter contains the following information o Section 7 2 provides an overview of o Section 7 5 discusses the effects of a loosely the Troubleshooting chapter mounted sample on measurement results o Section 7 3 discusses possible results o Section 7 6 discusses how high fields 14T and of a vibrating coilet above can affect magnetic measurements o Section 7 4 outlines how
101. he magnetic lock ring Important The sample will be subject to vertical magnetic fields of up to approximately 200 gauss when it passes through the head If this is unacceptable for your samples please contact your local Quantum Design service representative 4 Click on the Next gt gt button at the bottom of the VSM Install wizard If you have the VSM oven option then you will select Standard or Oven operating mode here 5 Open a new or existing output data file Note that all parameters entered here are for informational purposes only and are not used in calculating the reported sample moment 6 Click on the Next gt gt button at the bottom of the dialog Here you can Scan For Sample Offset or Enter Offset Manually if you used the sample mounting station to visually locate the sample e A sample signal larger than 10 emu is required in order to be detected in the centering scan This may require the application of magnetic field in order to magnetize your sample e Magnetic contamination and sample holder end effects can obscure the sample signal so it is recommended to verify the scan results with the known approximate sample offset of the sample e The Advanced Centering mode will locate the motor at a fixed height and will not permit touchdown centering Thus it is not generally recommended 4 4 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 4 Section 4 3 Taking VSM Measurements Inst
102. he o Section 3 3 explains how to mount samples that can be measured with the samples for measurement with the VSM VSM option option 3 2 Sample Properties The quality of your VSM measurement results will be affected by the dimensions and shape of the sample and the size of its magnetic moment 3 2 1 Size and Shape The geometry of the detection coils in the VSM constrains the dimensions of samples that can be measured Figure 5 4 gives the dimensions of a standard coilset puck In order for the sample and sample holder to fit into the detection coils without a high risk of rubbing against the coil set bore their diameter should be less than 4 mm Frictional heating especially at low temperatures and noise in the VSM measurements at high fields are common symptoms of friction between the sample holder and coil set Furthermore accurate results require samples that have a small vertical size compared to the baseline dimension of the detection coils For the standard coilset puck this baseline is 7 11 mm In practice a cylindrical sample in the shape of the included palladium standard sample is close to ideal Table 3 1 shows the calculated effect of the sample length and diameter on the reported sample moment The entries in the table were calculated for a vertically oriented cylindrical sample of length L and diameter D Each entry corresponds to the ratio of the reported moment to the true moment For example for a sample of length L 5 0
103. hours and minutes that will be needed to complete the measurement as well as the estimated number of lines in the output data file The number of lines in the output data file is also the total number of data points that will be generated by your measurement For instance there will be 17887 lines of data in the example measurement in Figure 6 32 6 9 3 Sequence Mode VSM Moment versus Temperature Dialog Advanced Tab The options in the Advanced tab Figure 6 29 of the sequence mode VSM Moment versus Temperature dialog control how the VSM takes data during a measurement Experienced users will notice that many sections of this tab are identical in form and function to sections of the immediate mode VSM Measurement dialog 6 9 3 1 CENTERING SETTINGS Use the Centering subsection of the Advanced tab to set the conditions for the VSM to perform touchdown operations For more information on Centering see Section 6 4 2 4 6 9 3 2 RANGING SETTINGS Use the Ranging subsection of the Advanced tab to set the way the system chooses the gain of the amplifiers in the VSM module during measurement For more information on Ranging see Section 6 4 2 5 6 9 3 3 PPMS DATA LOGGING SETTINGS The Select button in the PPMS Data Logging subsection opens the PPMS dialog Figure 6 17 which provides additional system information that you can have sent to the output data file For more information on PPMS Data Logging see Section 6 4 2 5 r Adva
104. ially available straws are not straight enough to be used for the VSM measurement The straws tend to bend and make contact with the chamber walls The frictional heating will restrict the base operational temperature In addition the friction of the straw end would cause noise in the VSM measurements Any loosening of the contact between straw and adapter would result in loss of accuracy that may not be obvious in data set It is difficult to secure the sample in the straw Because of these reasons straws are not recommended to use with VSM measurements Note that SVSM quartz paddle adapters are designed to fit a straw for protecting quartz The quartz tube is useful to mount a cylindrical sample as well as a bulk sample when the low background moment is important Clear plastic materials such as polycarbonate polypropylene and polystyrene are good candidates for low background moment holders due to their nonmagnetic material characteristics Avoid using colored plastic materials since the dyes used to color the plastics are generally magnetic Keep in mind that even though these plastic materials are good low moment candidates manufacturing environment might introduce magnetic contaminants to these materials Users should test these materials for the level of magnetic background Please e mail requests and suggestions to applications qdusa com Part numbers for relevant QD supplies 4096 385 4096 388 4096 390 4096 391 4096 392 4096
105. id helium and liquid nitrogen These precautions will protect you against cryogenic material hazards 1 they can expand explosively when exposed to room temperature 2 they can cause serious burns e ye Quantum Design Always wear protective clothing including thermal gloves eye protection and covered shoes when you work with liquid helium liquid nitrogen or other cryogens Avoid loose clothing or loose fitting gloves that could collect cryogenic liquids next to the skin The extreme cold of liquid and gaseous cryogens can cause serious burns and has the potential to cause loss of limbs Work with cryogenic materials in well ventilated areas only In the event a helium container ruptures or there is a helium spill vent the room immediately and evacuate all personnel In a poorly ventilated area helium can displace the air leading to asphyxiation Because helium rises well vented rooms with high ceilings generally provide the safest setting for working with helium VSM Option User s Manual 1096 100 Rev BO 1 5 February 2011 Section 1 5 Chapter 1 Contacting Quantum Design Introduction to the VSM Option 1 4 3 1 4 4 1 5 1 6 Electricity WARNING The VSM and the PPMS family of instruments are powered by nominal voltages that range from 100 V to 240 V AC These voltages are potentially lethal so you should exercise appropriate care before opening any of the electronics units inc
106. ile the power supply stabilizes the magnetic field at each set point the noise level might increase temporarily introducing artifacts into the VSM data until the system can achieve field stability Wait Time At Each Step The Wait Time At Each Step text box is used to set the additional time in seconds that you want the system to wait at each field set point This wait time is in addition to the amount of time it takes for the required VSM measurements and it is added before the VSM performs the measurements The Wait Time At Each Step setting has no effect if you have selected Sweep or Continuous Measuring modes Approach Mode The Approach Mode dropdown menu bar lets you choose between Linear No O Shoot No Overshoot and Oscillate field approach modes for each of the magnetic field set points in your measurement We recommend Linear mode when your Data Acquisition setting is Continuous Measuring Restore Defaults The Restore Defaults button resets everything in the dialog to the default settings 6 8 3 5 EXCITATION PARAMETERS Use the options in the Excitation Parameters subsection Figure 6 27 to set the drive variables for the VSM linear motor transport For more information on these options see Section 6 4 2 5 6 9 Sequence Mode VSM Moment vs Temp Command The VSM sequence mode Moment vs Temp command is designed to make these types of measurements easy to set up and execute in a sequence You can use the Moment vs
107. le Offset 1 Attach the sample to the sample holder using the techniques discussed in Chapter 3 2 Usethe sample mounting station to measure the distance from the center of the sample to the bottom of the sample holder reading the position from the scale as demonstrated in Figure 4 2 This distance is called the sample offset Measure the sample position to an accuracy of 0 5 mm The VSM hardware can safely accommodate a sample offset between zero 1 e sample is at the bottom end of the sample holder and 35mm However a sample offset less than 30mm can result in a significant signal from the magnetic end effect of the sample holder A sample offset larger than 35mm presents the risk of the sample holder rattling against the puck surface when measuring see Sec 4 2 1 1 TARGET LINE JA SAMBELE SCALE Figure 4 2 Reading the position of the sample from the sample mounting station 3 Remove the sample holder with the mounted sample from the mounting station and screw it firmly onto the end of the sample rod 4 Inspect the sample rod and sample holder to ensure they are straight Deviations can result in rubbing of the sample or sample holder in the coil set which causes heating at low temperatures and noise in the measured moment when a magnetic field is applied Quantum Design VSM Option User s Manual 1096 100 Rev BO 4 3 February 2011 Section 4 3 Chapter 4 Installing a Sample Taking VSM Measuremen
108. lling off the black plastic guard The lower fan for the power supply drawer can be cleaned by turning off the Model 1000 and vacuuming the outside of the filter Maintain a laboratory temperature below 25 C Keep the Model 1000 at least 25cm away from walls so that air flow is not impeded Cooling air inside the Model 1000 flows upward past the module and exits at the grate by the front plate of the modules Make sure these grates are unobstructed Try to minimize the dust level in the lab and keep the floors clean Connect all cables before activating the VSM option and do not unplug the motor drive cable while the option is activated Reconnecting the cable in this state can lead to motor malfunction Quantum Design is continually working to improve the handling of error conditions such as this by enhancing the software module firmware and module hardware Updates to option software such as the PPMS VSM option new service notes and application notes are posted on our website www qdusa com Firmware and hardware updates are handled on an individual basis by Quantum Design service If you are encountering performance problems with your motor module after observing the above maintenance steps please contact your local Quantum Design service representative Quantum Design VSM Option User s Manual 1096 100 Rev BO A 9 February 2011 A PP E NDIX B Model CM B VSM Detection Module B 1 Introduction This appendix contai
109. luding turning off the equipment and disconnecting it from its power source Turn off and unplug all electronic equipment before removing any equipment covers S Keep electrical cords in good working condition and replace frayed and damaged cords e Keep liquids away from the workstations Lifting and Handling The VSM linear motor transport 4096 400 should be handled with care as it is very heavy about 10 kg or 22 Ib and could cause crushing injuries Contacting Quantum Design If you have trouble with your VSM or your system please contact your local Quantum Design service representative for assistance See www qd international com for the information about your local representative You will be asked to describe the problem the circumstances involved and the recent history of your system VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 C H APTER 2 Installing and Removing the VSM Option 2 1 Introduction This chapter contains the following information o Section 2 2 lists the components of o Section 2 3 describes the procedures theVSM option and describes the you will use to deactivate and procedures you will use for the initial remove the VSM option so that you installation on the system can use a different measurement option 2 2 Initial Installation of the Hardware and Software This section describes the procedures you will use for the initial installatio
110. lvents 2 Easily obtained Duco cement is useful at room temperature and for securing materials of similar thermal properties like quartz on quartz Differing materials will force cracking in the brittle Duco cement upon cooling below 150 K Duco may go on thick but it will dry or cure to a thin residue A key reason for regular use is Duco solubility in acetone Powders secured with Duco can be easily recovered by soaking in acetone Quantum Design VSM Option User s Manual 1096 100 Rev BO 3 7 February 2011 Section 3 3 Mounting Samples Chapter 3 Sample Preparation and Mounting Easily obtained Superglue cyanoacrylate is a fast drying very secure bonding method for room temperature measurements The very thin nature allows low mass low magnetic signature application At the colder temperatures it may not hold materials with different thermal properties The solvent of choice is nitro methane Still readily available as a stock car fuel it should be handled carefully A cotton swab of nitro methane with a thin stick to wedge the sample off the holder should work effectively Please see MSDS for proper ventilation requirements when using these solvents The Zircar cement is conveniently water based and supplied with the VSM oven user kit The primary purpose of application to over 1100 K has been verified Used in conjunction with tight wrapping of copper foil provides a sufficiently robust design for VSM style measurements The VSM o
111. mber of data points the VSM will take at each of the fields shown in the Approximate Fields list This option has no effect 1f you have selected the Sweep or Continuous Measuring mode Keep The Keep dropdown menu bar Figure 6 26 is only available when you have selected Continuous Measurement which can generate large volumes of data Use the Keep options to choose a percentage of VSM data points that will be written to the data file See the Estimated explanation below for more on this issue Field Control Approximate Fields Sweep Rate ro Oe sec 4l Driven at each field Persistent at each field Sweep End Mode Persistent z m Data Acquisition Averaging Time fi sec c Number eff ede 5 Field Increment so De Repetitions at IL Estimated each Field npe Time 00 42 h m Keep all measurements m Lines 2501 all measurements E 50 of measurements 20 of measurements 10 of measurements 5 of measurements 2 of measurements 1 of measurements Figure 6 26 Data Acquisition Keep and Approximate Fields settings 6 16 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Figure 6 25 Data Acquisition Chapter 6 Section 6 8 VSM Software Sequence Mode VSM Moment vs Field Command 6 8 2 4 APPROXIMATE FIELDS The Approximate Fields list Figure 6 26 displays in sequence a close estimate of the fi
112. mm and diameter D 2 0 mm measured with a peak amplitude A 2 0 mm the software will report a numerical result for the moment that is 0 9476 times the answer obtained for a pointlike sample of the same total moment Note that while the values in Table 3 1 have been normalized to 1 0000 for a pointlike sample the VSM system is calibrated against the palladium standard sample L 3 8mm D 2 8mm at a peak amplitude A 1 0 mm Quantum Design VSM Option User s Manual 1096 100 Rev BO 3 1 February 2011 Section 3 2 Chapter 3 Sample Properties Sample Preparation and Mounting Table 3 1 Calculated ratio of the reported moment to the true moment for different size cylindrical samples and different amplitudes SAMPLE DIMENSIONS PEAK AMPLITUDE OF SAMPLE OSCILLATION Bag fecha i bed D 0 5 mm 1 0 mm 2 0 mm 0 0 1 0000 1 0000 1 0000 0 1 1 0003 1 0005 1 0014 0 2 1 0007 1 0017 1 0053 0 3 1 0005 1 0026 1 0109 1 0 0 9996 0 9993 0 9981 1 1 0 9999 0 9999 0 9996 1 2 1 0007 1 0013 1 0037 1 3 1 0010 1 0028 1 0097 2 0 0 9978 0 9966 0 9921 2 1 0 9985 0 9975 0 9937 2 2 1 0002 0 9999 0 9986 2 3 1 0020 1 0029 1 0059 3 0 0 9933 0 9906 0 9808 3 1 0 9944 0 9920 0 9828 3 2 0 9976 0 9958 0 9887 3 3 1 0020 1 0013 0 9980 5 0 0 9662 0 9597 0 9367 5 1 0 9687 0 9622 0 9394 5 2 0 9759 0 9698 0 9476 5 3 0 9877 0 9820 0 9613 10 0 0 6961 0
113. mple location not in the middle of the sample chamber In other words it takes several hours for the thermal profile of the sample chamber to stabilize after a new sample temperature is established In this case the chamber appears to be expanding slightly over these 4 hours which could be due to the fact that the very fast cool down under cooled the middle part of the sample chamber The one exception to this is on the 16 tesla PPMS system in which the large magnetic field gradients cause the motor to be pulled down slightly at high magnetic fields necessitating sample centering as a function of magnetic field Quantum Design VSM Option User s Manual 1096 100 Rev BO 7 3 February 2011 Section 7 4 Chapter 7 Sample Centering and Temperature Dependent Troubleshooting Magnetization Measurements powder cap chamber equil dat 2 PPE powder caps pressed together gap 0 dT dt 7 5 K min EI v 5 E a E a g Center Position mm 10 8 5 10 10 0 7280 a0 Time Stamp minutes relative Figure 7 1 VSM data file showing change in sample position as temperature is lowered Note Log temperature axis The reason that sample centering 1s so important is that the reported magnetic moment depends on the vertical position of the sample relative the center of the coils To understand how an error in vertical centering translates into an error in the reported moment one must perform a cent
114. mple rod until the end of the sample holder touches the puck surface see Figure 4 1 At this point the software knows the precise offset between the coilset and the sample based on the dimensions of the coilset and the location of the sample on the sample holder The linear motor transport then moves the center of the sample to the center of the coilset to continue measuring according to the following relation Measure location touchdown location coilset height sample offset where coilset height H in Figure 5 4 is a calibrated constant for a given puck and is near 40mm SAMPLE ROD J E Z L E 5 SAMPLE HOLDER OILS SAMPLE TOUCHIN TOUCHDOWN CENTERED Figure 4 1 The touchdown centering operation 4 2 1 2 SCHEDULING TOUCHDOWN OPERATIONS The software usually performs touchdown operations automatically at prescribed intervals of temperature typically 10 K or time typically 10 minutes Touchdowns can also be performed explicitly in a sequence VSM gt gt Center Sample in immediate measurement mode Measure gt gt VSM Center Sample in the MultiVu dropdown menu CAUTION Failure to perform frequent enough centering operations will lower the accuracy of measurements Automatic centering is a key quality control mechanism in the software When automatic centering has been disabled the software cannot know how far the sample has drifted from the center of the pickup coils unless a touchdown is perform
115. n of the Quantum Design Vibrating Sample Magnetometer VSM These procedures apply only to the first time you set up and use the VSM option To re install the VSM option after it has been deactivated and a different measurement option e g the Heat Capacity option has been used you will use the procedures in Section 2 3 Reconfiguring the system for the VSM Option Important Parts of the initial installation may have been performed at the factory if the VSM option was purchased as part of a new system Table 2 1 lists the components of the Quantum Design VSM option Verify that you have received all the components before you start the installation process Quantum Design VSM Option User s Manual 1096 100 Rev BO 2 1 February 2011 Section 2 2 Chapter 2 1BInitial Installation of the Hardware and Software Installing and Removing the VSM Option Table 2 1 VSM system components COMPONENT PART ILLUSTRATION NUMBER Linear Motor Transport sometimes referred to as 4096 400 Figures 2 1 2 6 5 1 the Head or the VSM Transport Extender tube flange sometimes referred to as the 4096 418 or Figures 2 6 5 1 Bottom Weldment Flange and O rings 4096 450 and VON2 030 Storage Case 4096 150 Figure 5 2 Coilset Assembly 4096 204 or Figures 2 1 2 2 2 3 4096 600 5 3 5 4 Sample Tube 4096 301 Figures 2 1 2 4 2 5 5 5 4096 620 4096 350
116. nced Settings 6 9 3 4 ADVANCED SETTINGS v Require Sweep Mode For Continuous Acquisition The Advanced Settings subsection Wait Time t E Figure 6 33 is a general section for ES gud E estore controls that are rarely used Approach Mode Fast Defaults Figure 6 33 Advanced Settings section Require sweep Wait Time and Approach Mode 6 22 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software 6 10 Section 6 10 VSM Data Files Require Sweep Mode For Continuous Acquisition The system will automatically activate the Require Sweep Mode For Continuous Acquisition option when Continuous Measurement data acquisition has been selected Note You can uncheck the box and use the Stabilize at each Temperature mode while you perform continuous measurements However be aware that if you measure continuously while the controller is stabilizing the temperature the amount of noise in the VSM data might increase Wait Time At Each Step The Wait Time At Each Step value sets the additional time in seconds that the system waits at each of the temperature set points This wait time is in addition to the amount of time it takes to do the required VSM measurements it is added before the VSM performs the measurements This setting has no effect if you have selected Sweep or Continuous Measuring modes Approach Mode The Approach Mode dropdown menu bar lets you choose between Fast and No O
117. nd electrical VSM motor module specifications o Section A 3 describes the front panel and Section A 5 describes maintenance of the relevant components of the Model CM A Model 1000 VSM motor module A 2 Functional Overview The Model CM A 4101 100 is a servomotor controller module that was designed with the specific needs of the VSM head in mind Figure A 1 shows the module and the front panel The principle function of this module is to provide closed loop servo control to a linear motor equipped with a position encoder output A programmed wave table allows the module to drive the motor sinusoidally at 40 Hz The servo loop is closed digitally at about 2000 Hz using a 16 bit current source and the read back from the position encoder For use with other synchronous detection hardware including the Model CM B VSM detection module the real time encoder position is output digitally using a high speed serial port and as a voltage through a BNC connector Other features include in system programmable on board flash memory for program storage and a serial ROM for calibration and other configuration data The module is designed to plug into the Model 1000 modular control system or an equivalent host chassis that can provide power and the required CAN network signals that communicate with the module Quantum Design VSM Option User s Manual 1096 100 Rev BO A 1 February 2011 Section A 2 Appendix A 1BFunctional Overview Model CM A VSM Mo
118. nd service notes have been incorporated into this version of the manual and those include Application Notes e VSM Sample Mounting Techniques 11 10 1096 306 e Sample Centering and Temperature Dependent Magnetization Measurements using the PPMS VSM 6 10 1096 305 e Mounting Samples Loosely Causes Moment Noise in VSM Measurements 9 04 1096 303 e Performing VSM Measurements in PPMS High Field 14 T or Higher Magnets 11 03 1096 301 Service Notes e Operating Guidelines for the Motor Module used for VSM 6 10 1096 307 This space is reserved for any relevant application and service notes that have been added after the release of this manual Please check the Quantum Design website www qdusa com regularly for technical note updates and new postings Quantum Design VSM Option User s Manual 1096 100 Rev BO C 1 February 2011
119. ne eene enne entretenir innen en 6 15 6 8 24 Approximate Fields 1e E eee eh ata creer ath eis 6 17 6 8 2 5 Bstimated ione nie uei DRE Rte uet eb EEE EEE 6 17 6 8 3 Sequence Mode VSM Moment versus Field Dialog Advanced Tab 6 17 6 8 3 1 Centering Settings ueeec ne eter De it ha LE Pea ende ere ete te eene 6 17 6 8 3 2 Ranging Settings ose reir er Re ERRORI MIT METERS ERR exis 6 17 6 8 3 3 PPMS Data Logging Settings 6 17 6 8 3 4 Advanced Settimgs eei eo ete etae tee ete ice A a i aaea 6 17 60 8 3 5 Excitation Parameters eee ek dee eee 6 18 6 9 Sequence Mode VSM Moment vs Temp Command serene 6 18 6 9 Sequence Mode VSM Moment versus Temperature Dialog eese 6 18 6 9 2 Sequence Mode VSM Moment versus Temperature Dialog Setup Tab 6 19 6 0 2 1 Temperature Control SettihgSaisere irena a a nennen rennen 6 19 6 9 2 2 Data Acquisition Set eS unio cotta E IRE PRI Pede I RE EEE 6 20 6 0 2 3 Approx Temperatures 00 0 ceccceeccccesecesseceeseeceeeeeceaceeesaeceeaecseaeeceeeeesaecseaaeceeneeees 6 22 6 9 2 4 Estimated use Er nien pete baal eels 6 22 6 9 3 Sequence Mode VSM Moment versus Temperature Dialog Advanced Tab 6 22 6 9 3 L Centering Settings sae sonet e mer pe eet beet gre S 6 22 Quantum Design VSM Option User s Manual 1096 100 Rev BO vii February 2011 Contents Table of Contents
120. ng safety guidelines when you use your system To avoid damaging the system verify that the system power requirements match the alternating current AC power available at your location If the system has not been configured for the correct power available at your location contact your local service representative before you proceed with the system installation To prevent electrical shock verify that the equipment is properly grounded with three wire grounded plugs To prevent electrical shock unplug the system before you install it adjust it or service it Do not spill food or liquids on the system or its cables Refer to the section titled Safety Precautions before you install or operate this system Direct contact with cryogenic liquids materials recently removed from cryogenic liquids or exposure to the boil off gas can freeze skin or eyes almost instantly causing serious injuries similar to frostbite or burns Wear protective gear including clothing insulated gloves and safety eye protection when you handle cryogenic liquids Transfer liquid helium only in areas that have adequate ventilation and a supply of fresh air Helium gas can displace the air in a confined space or room resulting in asphyxiation dizziness unconsciousness or death Keep this system away from radiators and heat sources Provide adequate ventilation to allow for cooling around the cabinet and computer equipment Refer to the manuals for the
121. nnector for the Model CM A VSM motor module A 4 JA 3 Motor sync connector for the Model CM A VSM motor module A 5 JA 4 Aux connector for the Model CM A VSM motor module A 6 QD CAN connector on the rear of the Model CM A VSM motor module A 8 Electrical specifications for the Model CM B VSM detection module B 3 LED guide for the Model CM B VSM detection module sess B 3 JB 1 Motor sync connections for the Model CM B VSM detection module B 4 JB 3 Preamp connector for the Model CM B VSM detection module B 5 QD CAN connector on the rear of the Model CM B VSM detection module B 7 VSM Option User s Manual 1096 100 Rev BO xiii February 2011 P RE FA C E Contents and Conventions P 1 Introduction This preface contains the following information o Section P 2 provides an overview of the o Section P 4 shows the conventions that scope of the manual appear in the manual o Section P 3 outlines the contents of the manual P 2 Scope of the Manual This manual contains background about the PPMS Vibrating Sample Magnetometer VSM option as well as instructions for using the VSM software and hardware and performing sensitive measurements when the VSM is installed in the PPMS unit P 3 Contents of the Manual o Chapter 1 provides an overview of the VSM option and the th
122. ns the following information o Section B2 provides a functional o Section B 4 describes the back panel overview of the Model CM B VSM and relevant components of the Model detection module including a block CM B VSM detection module diagram and electrical specifications o Section B 3 describes the front panel and relevant components of the Model CM B VSM detection module B 2 Functional Overview The Model CM B 4101 150 is a synchronous detection module that performs the real time signal processing for the VSM option The module and its front panel are shown in Figure B 1 The principle function of this module is to detect the in phase and quadrature phase components of one or two input signals e g pickup coils as well as a digital reference from say a position encoder The detection is done by multiplying each of the signals by both a sine function and a cosine function These sine components are computed once per cycle and can be output at this rate or they can be averaged for multiple cycles with statistics calculated for the ensemble of measurements Other features include a thermometer bridge circuit for temperature measurements two programmable gain amplifiers in system programmable on board flash memory for program storage and a serial ROM for calibration and other configuration data The module is designed to plug into the Model 1000 modular control system or an equivalent host chassis that can provide power and the req
123. nsport and its operations WINDOW LOAD POSITION RUN POSITION SHUTDOWN POSITION ELECTRICAL EXTENDER TUBE NNECTOR FLANGE REAR VIEW SHIPPING PLUG FRONT VIEW Figure 2 6 Front and rear views of the VSM linear motor transport 4096 400 The rear view right shows the transport with the shipping plug installed in the front view left the shipping plug has been replaced by the extender tube flange 2 6 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 2 Section 2 2 Installing and Removing the VSM Option 1BInitial Installation of the Hardware and Software CAUTION Use care when installing the VSM linear motor transport it is fragile bulky and moderately heavy about 10 kg or 22 Ib Always use the VSM specific parts e g the centering rings to ensure that the equipment operates safely and properly Always use the flange clamp Figure 2 7 to hold the linear motor transport onto the stabilizer post 1 Prepare the extender tube flange e Locate the extender tube flange and the flange O ring part number VON2 030 e Wipe the neck of the flange with a lint free cloth e g Kimwipe to remove any dust or dirt e Place the O ring into the neck of the extender tube flange Firmly press on the O ring to assure it Is completely seated e Wipe the O ring and lightly grease it with silicon vacuum grease e Place the extender tube flange on a clean piece of paper or lint f
124. nute during a measurement The Moment vs Temp sequence command interprets the Sweep Rate as a magnitude and uses the Start and End temperatures to determine the sign of the temperature sweep rate Note If you choose to stabilize the temperature during measurements the Sweep Rate will become the rate of temperature change between temperature set points instead of the overall rate of temperature change Stabilize at each Temperature and Sweep Continuously The Stabilize at each Temperature and Sweep Continuously options provide two modes for sweeping temperature When you select Stabilize at each Temperature the system waits for the temperature to stabilize at each of the set points listed in the Approx Temperatures window before it begins to take data When you select Sweep Continuously the system changes temperature at the Sweep Rate setting while the VSM takes data and it does not pause at the set points listed in the Approx Temperatures window 6 9 2 2 DATA ACQUISITION SETTINGS Use the options in the Data Acquisition subsection of the dialog box to set the basic parameters of the moment versus temperature measurement Data Acquisition Data Spacing Uniform Spacing in Temp The Data Spacing dropdown menu bar at the top of the section provides the following options second Time dd o Continuous Measuring Figures 6 28 c Number of eo and 6 32 sets the VSM to take data in pe ate t Continuous Measuring mode refer t
125. o est adage 5o Section 6 2 4 3 for more information on Continuous Measuring When you are Repetitions at each m not using Continuous Measuring you Temper must define the temperature change between measurements as is explained below in Number of Temperatures and Temperature Increment Keep all measurement Figure 6 31 Data Acquisition section of the sequence mode VSM Moment versus Temperature dialog o Uniform Spacing in Temperature Figure 6 31 sets the VSM to take data at uniform temperature intervals o Uniform Spacing in Temperature 2 sets the VSM to take data at uniform temperature intervals with respect to the square of the temperature o Uniform Spacing in Temperature 1 2 sets the VSM to take data at uniform temperature intervals with respect to the square root of the temperature 6 20 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 VSM Software Quantum Design Section 6 9 Sequence Mode VSM Moment vs Temp Command o Uniform Spacing in 1 Temperature sets the VSM to take data at uniform temperature intervals with respect to the inverse of the temperature o Uniform Spacing in Log Temperature sets the VSM to take data at uniform temperature intervals with respect to the logarithm of the temperature Averaging Time The Averaging Time value Figures 6 31 and 6 32 sets the length of time the VSM collects data before it is averaged into a measurement Section
126. om Select 4 Serial Com Data MOSI 5 Thermometer Current 6 Thermometer Voltage 9 15V 10 Channel 1 Input 11 5V 12 Channel 2 Input 13 Signal Ground 16 Serial Com Clock 17 Serial Com Data MISO 18 Thermometer Current 19 Thermometer Voltage 22 15V 23 Channel 1 Input 25 Channel 2 Input Quantum Design VSM Option User s Manual 1096 100 Rev BO B 5 February 2011 Section B 4 Appendix B 3BModel CM B Detection Module Rear Panel Model CM B VSM Detection Module B 4 B 4 1 B 4 2 B 6 Model CM B Detection Module Rear Panel The rear panel of the Model CM B VSM detection module contains an address selector two guide holes and the CAN connector through which the module sends and receives network data and receives power Address Selector Each module on the CAN bus must have a unique 5 bit binary address The selector on the back panel is used to set the four least significant bits while an internal jumper sets the most significant bit If the selector is set to 0 the module uses its default address For a Model CM B VSM detection module the default address is 8 Guide Holes The two guide holes are used to align the connector with either a low power receptacle or a high power receptacle on the Model 1000 modular control system ADDRESS SELECTOR Figure B 5 Rear panel of the Model CM B VSM detection module VSM Option User s Manual 1096 100 Rev BO Quantum
127. on select it on the right side and click Deactivate in this dialog PPMS Multivu Simulation Mode File View Sample Sequence Measure Graph Instrument Utilities Help SM SIM No Datafile Install Data File Sample Advanced Chamber Status 1 90K Stable Purged and sealed Install Femove Configure VSM Sample System Status Measure Help VSM Ready Sequence Idle 296 40 K Stable 9025 0 Oe Persistent Im Seq none Set30410K Set 41 0 0e E lt none gt 12 00 K min Fast Settle 100 0 De sec Linear E Figure 6 2 The MultiVu window and the VSM Control Center VSM SIM including the Install tab the VSM Status area and the MultiVu Status bar Note that the VSM Log window has been minimized 6 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 Section 6 3 VSM Software VSM Dropdown Menus 6 3 VSM Dropdown Menus VSM specific actions dialogs and commands are incorporated into the View Sample and Measure dropdown menus in the MultiVu window after you have activated the option The other dropdown menus in the MultiVu window contain menu items that are common to all Quantum Design systems 6 3 1 View You can use the View dropdown menu at the top of the MultiVu window Figure 6 3 to open VSM specific dialogs as well as to perform general actions such as opening and closing the MultiVu Status Bar the Sequence Control bar at the side of the window or the tool
128. on 3 3 Sample Preparation and Mounting 2BMounting Samples The hydrostatic pressure cells by various vendors require securing the sample for the VSM style measurements The GE7031 varnish has proven effective for room temperature analysis of dysprosium oxide pellet pieces The Teflon bucket for organic solvents or air sensitive samples was originally designed for the PPMS ACMS instrument The length was shortened for the MPMS XL with RSO instrument and is particularly useful with SQUID based AC susceptibility measurements Now there are new lengths for both the PPMS VSM with the large bore coil set or the SQUID VSM Simply reverse the blue adapter male threaded piece and glue carbon fiber rod with lid of bucket The torque and vibrations should require extra security in securing the threaded top Teflon tape or layer of epoxy on the threads will help maintain a tight fit Components like quartz braces and Quantalloy supports need to be longer for the SQUID VSM as compared to the PPMS VSM due to the larger axial dimension of the second order gradiometer The aluminum large area pictured below thin film holder using mechanical technique is only applicable to the large bore coil set dimensions The lightweight design allows a large surface area for securing a sample with a clamp and screw mechanical device It was designed originally for use with 9 x 9 x 0 5mm thin film samples Straws and gelatin capsules are no longer being used The commerc
129. on User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 3 Section 3 3 Sample Preparation and Mounting 2BMounting Samples epoxy requires avoiding contact with cleaning solvents Cotton swab soaked in appropriate solvent and let set against old glue until swab is dry Apply a new soaked cotton swab to loosened glue and remove without risking the gold plating Under the general principle of uniform mass of the holder for 3 cm from the sample location keeping a uniform gold coating is relevant to the background contribution Pictures of cleaning supplies Specific cotton swab for brass trough iso propanol IPA acetone toluene nitro methane a Ral OE n ala Fisherbrand Non Sterile Swabs Cotton Tipped 3 Wood Handle COTTON TIPPED APPLICATORS Cat No 14 960 3N Contains 10 Packs ishor selenite ono nis com 2 Justa few of the methods and materials for securing the sample to the holder are presented The primary goal is to keep the sample a point source dipole during the measurement Since any glue or tape will introduce point source dipole contributions to the total magnetic moment the material should be applied sparingly and symmetrically A The press fit into brass trough holder achieves all the ideal aspects of a secure sample mounting without the need for extra glue One concern is a transfer of material to the holder but routine blank measurement checks will confirm the low level back
130. on as temperature is lowered 7 4 Centering scan data taken in 1 tesla applied field for the sample used in this investigation left as well as an ideal sample right ssesssss 7 5 Showing artifact in reported moment due to errors in vertical centering 7 6 Magnetization vs temperature data for nickel with sample rattling in the sample holder below 290 KK 6 be etn ees eet dte ot EE Re eee 7 7 Oscilliscope trace of 40 Hz coilset signal measured at the BNC on the VSM regule 7 8 The effect of flux jumps on VSM moment versus field data during ramping and stable fields when using a 14 T magnet at fields between 2 T to 2 T 7 9 Model CM A VSM motor module 4101 100 eese A 2 Abridged functional block diagram of Model CM A VSM motor module SDeCITICAtIODS nid epe terio ripetere Hobart Hee TELE Cere p eret DE ent que A 2 JA 1 Servo connector for the Model CM A VSM motor module A 4 JA 3 Motor sync connector for the Model CM A VSM motor module A 5 JA 4 Aux connector for the Model CM A VSM motor module A 6 Rear panel of the Model CM A VSM motor module see A 7 Quantum Design CAN connector for the Model CM A VSM motor module A 8 Model CM B VSM detection module 4101 150 sse B 2 Abridged functional block diagram of the Model CM B VSM det
131. ortant that the detection coil set 1s immobile because any vibrations of it relative to the magnetic field will create induced voltages A coil with many windings and which is located in a very large and slightly non uniform magnetic field will be a very sensitive microphone The VSM sample rod is guided by special blue plastic alignment bearings in the sample chamber There is necessarily some friction as the sample rod oscillates and this can transmit vibrations into the coil set In addition direct rubbing of the sample in the coil set can occur if the sample rod sample holder assembly is not straight or if the sample is large diameter and contacts the inner bore of the coil set directly These induced vibrations are of the same frequency as those due to the moving sample and so are indistinguishable from sample signal by the lock in amplifier Fortunately this signal statistically appears equally in both the Moment and M Quad Signal quadrature moment or 90 degree phase lagged in time values Since this quadrature portion is not due to the sample s magnetic moment to a precision of lt 0 5 signal here will be a very helpful clue in understanding the magnitude of the parasitic signal in the reported moment Methods of mitigating these unwanted coil set vibrations are outlined below 1 Ensure the sample rod and sample holder are straight by viewing down the length and rotating the rod Excessive wobble will lead to increased chance
132. our samples please contact Quantum Design CAUTION The indicator pin should be at the bottom of the window when the linear motor transport has been shut down If it is NOT it indicates that the sample rod has been inadvertently left in the sample chamber Never attempt to remove the linear motor transport from the system while the sample rod is installed SAMPLE ACCESS I iD MAGNETIC LOCK RING ELECTRICAL CONNECTOR EXTENDER TUBE FLANGE IR REAR VIEW SHIPPING PLUG FRONT VIEW Figure 5 1 VSM linear motor transport 4096 400 5 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 5 Section 5 2 VSM Hardware VSM Hardware Components 5 2 2 5 2 3 Storage Case for Linear Motor Transport Because the linear motor transport is both heavy and delicate Quantum Design has furnished you with a specially designed storage case to protect it during transport and storage When the linear motor transport is not being used it should be stored in this case You can keep the case on a shelf or in a cabinet so long as it is on a stable base and is stored upright as shown in Figure 5 2 CAUTION Because the storage case has a high center of gravity it is critical that you place it on a very stable base such as the floor Figure 5 2 Storage case 4096 150 for the linear motor transport Coilset Puck The coilset puck contains the VSM detection coils
133. pacing between the fields with one of these options Figure 6 25 Note that when you select one of these settings you must enter a number in the associated text box before you will be able to take measurements Number of Fields and Field Increment o To set the number of times the VSM will measure between your selected Hmax and Hin click on the button next to Number of Fields Min to Max The value you enter into the text box next to Number of Fields Min to Max sets the number of data points the VSM will take between Hmax to Hmin including Hmax and Hmin spaced uniformly in the manner you have selected o To directly set the increment in magnetic field between VSM data points click on the button next to Field Increment If you select the Field Increment radio button you must enter a number in the associated text box If you set a step size that does not fit evenly with your selected Hmax and Hmin the program will adjust the increment size slightly to include Hmax and Hyin Note Because uniform spacing is referenced between Hmax and Hin the field you enter for Ho might not be used in the measurement if the combination of uniform spacing and number of fields does not line up evenly with Ho If this occurs Hg will only be included as a data point if it is selected as the starting or ending field or both of the measurement Repetitions at each Field The value entered for Repetitions at each Field Figure 6 26 is the nu
134. ponents VSM Hardware INTEGRATED CENTERING RING STABILIZER POS BAFFLES CENTERING BAFFLE Figure 5 5 VSM sample tube 4096 301 shown for example 5 2 5 Sample Rod Many of the design features of the sample rod were introduced to reduce the background signal from mechanical vibrations at the VSM oscillation frequency Such features control the rattling or friction between the rod and the system and they eliminate resonant flexure of the shaft MAGNETIC LOCK CENTERING SLIDES FLEXIBLE COUPLING STIFF TAPERED CORBON EIBER FLEXIBLE THIN LOWER SLIDE SHAFT CARBON FIBER ADAPTER SHAFT Figure 5 6 VSM sample rod 4096 352 shown for example Figure 5 6 shows the sample rod in a horizontal position during use the magnetic lock would be at the top of the rod Important Keep the magnet surfaces clean as the strength of the lock depends on the magnets being flush in contact with the mating part in the linear motor transport Also avoid bringing the magnets into contact with magnetic objects Although small the magnets are extremely strong 5 6 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 5 Section 5 3 VSM Hardware VSM Option User s Kit KI VSM Option User s Kit The VSM Option User s Kit contains miscellaneous hardware and supplies that you will use to mount samples and to verify the operation of the VSM The convenient portable toolbox see Figure 5 7 helps organize the items
135. ption User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 1 Section 1 4 Introduction to the VSM Option Safety Precautions are dangerous to anyone who has a metallic implant or is wearing a pacemaker or other electrical or mechanical medical device Important The automated control system can turn on the magnet while the system is unattended Furthermore the three dimensional magnetic field will penetrate nearby walls the ceiling and the floor Therefore your safety considerations should include such adjacent spaces Keep all iron nickel and other ferromagnetic objects at least 5 m 16 5 ft from the dewar Large magnets such as superconducting magnets can attract iron and other ferromagnetic materials with great force Never attempt to install remove or handle the VSM linear motor transport 4096 400 when there is a field set in the system or in any other nearby equipment In addition the VSM linear motor transport must be secured when it is stored within 5 m 16 5 ft of the system or any other large field source The VSM linear motor transport contains nearly 9 kg of iron which presents a considerable hazard in a large magnetic field such as that produced by the system or other laboratory equipment such as an NMR magnet 1 4 2 Cryogens if applicable WARNING Always wear protective clothing and ensure that the room has good ventilation when you work with cryogenic materials such as liqu
136. ree cloth until it can be installed 2 Remove the VSM linear motor transport and its stand from the storage case and place them on a stable work surface keeping the motor in a vertical position Remove the shipping plug from the bottom of the motor see Figure 2 6 4 Verify that the O ring of the extender tube flange is still in place and its exposed surface is clean If it is dusty or dirty clean it and lightly grease it with silicon vacuum grease 5 Screw the extender tube flange onto the bottom of the motor until it is tightly attached using Figure 2 6 for an example Hand tighten the tube only 6 Remove the VSM linear motor transport from the stand keeping it upright For example you can support the weight of the linear motor transport by gripping it with one hand on the top tube and the other hand on the extender tube flange 7 Place the VSM linear motor transport onto the top flange of the system by orienting the electrical connector to the rear of the cryostat The linear motor transport should slide over the stabilizer post at the top of the VSM sample tube assembly Figure 2 7 shows where the stabilizer post emerges from the sample chamber the correct orientation of the linear motor transport and other relevant parts of the equipment 8 Verify that the integrated VSM centering ring 1s sandwiched snugly between the top flange and the linear motor transport 9 Attach the flange clamp to the flange Always use the flange
137. romagnets with a very sharp hysteresis loop and range changing is not desired Data Logging Cn ln General Status Brg Ch 1 Resistance Map 20 In the Data Logging area of the VSM Beas j ap C IC Ad d tab th Temperature Brg Ch 1 Excitation Map 21 ontrol Center vanced tab the Magnetic Field Brg Ch 2 Resistance Map 22 Select button opens the dialog lt 1 ESI SI Brg Ch 2 Excitation Map 23 Figure 6 17 which lists additional eee Bip Cha Resistance Map 24 system data items that you can choose Digital Inputs Brg Ch 3 Excitation v Sample K to add to the current data file These DrCh 1 Current Brg Ch 4 Resistance Map 26 items are in addition to the VSM data nieni Pone Brg Ch 4 Excitation C Map 27 items that are typically included DrCh2Curent SigCh 1 Input Voltage J7 Map 28 which are summarized in Table 6 1 DrCh 2 Power Sig Ch 2 Input Voltage Map 29 OK Close Help Figure 6 17 Data logging dialog for selecting additional types of data to be collected Overview of Sequence Mode VSM Commands VSM sequence mode commands are essentially encapsulated versions of VSM immediate mode measurement commands VSM Adv Measure Center Sample Moment vs Field and Moment vs Temp sequence commands can be combined with non VSM sequence commands and looping constructs The VSM sequence mode commands have interactive dialogs that help you specify your measurements and th
138. rty Measurement System PPMS family of instruments is a fast and sensitive DC magnetometer The basic measurement is accomplished by oscillating the sample near a detection pickup coil and synchronously detecting the voltage induced By using a compact gradiometer pickup coil configuration a relatively large oscillation amplitude 1 3 mm peak and a frequency of 40 Hz the system is able to resolve magnetization changes of less than 10 emu at a data rate of 1 Hz The VSM option consists primarily of a VSM linear motor transport head for vibrating the sample a coilset puck for detection electronics for driving the linear motor transport and detecting the response from the pickup coils and a copy of the MultiVu software application for automation and control Notable Features of the VSM System The Quantum Design VSM linear motor transport uses a uniquely designed linear motor to vibrate the sample Unlike other vibrating sample magnetometers that use a short throw resonant voice coil design you will find that the VSM linear motor is designed to operate at 40 Hz with Quantum Design VSM Option User s Manual 1096 100 Rev BO 1 1 February 2011 Section 1 3 Chapter 1 Theory of Operation Introduction to the VSM Option rapid slewing possible over about 6 5 cm of travel The large range of motion enables the VSM system to perform rapid completely automated centering operations you will not need to perform manual adjustments to center
139. s deposited on the silicon substrate 100 it 1s easy to cut a rectangular or square piece along 110 directions Place two pieces of samples with a film side face to face and mount the pair vertically on the quartz paddle with an appropriate fixture using varnish or one of the glues Two pieces of films increase the signal and help them stand perpendicular to the quartz paddle 4 Polypropylene powder holder is an injection molded plastic part that snaps into the brass trough The figure below shows the shapes of all are identical Sample mass from 1 mg to 10 mg of powder is put into the opening A second piece will compress the powder and seal the combination The assembly snaps into the brass trough for a secure press fit The material covers the entire temperature range from 1 8 K to 400 K This powder holder is not recommended for liquid samples so please refer to the section on custom mounting techniques A guide to the complete experiment is as follows e Inspect and clean the brass trough and both polypropylene powder holders Quantum Design VSM Option User s Manual 1096 100 Rev BO 3 5 February 2011 Section 3 3 Chapter 3 Mounting Samples Sample Preparation and Mounting e Allow for the appropriate sized gap as the 2 pieces are joined as will occur when the sample is later used Snap rigidly into place within the brass trough Measure the distance from end of brass trough to center of gap location using mounting station e Ins
140. s of contact with the coils Note that perfect straightness is not possible to achieve 2 Ensure the sample diameter is less than coil set bore 2mm The standard coils have a 6mm bore while the large bore coil set is 12mm It is helpful to have a large bore coil set P529 on hand in order to rule out such frictional 1ssues 3 Cutthe vibration frequency in half typically from 40 Hz to 20 Hz and remeasure As the accelerations and forces scale with the square of the vibration frequency this means a 75 decrease in forces and may in some cases provide a dramatic improvement Note that the VSM hardware is calibrated only near 40 Hz so it is important to check the calibration using the Pd standard sample if a new frequency is chosen To change the vibration frequency for a one time test this can be simply typed into the box in the Advanced tab of the VSM measure dialog To change the dropdown menu of available frequencies in this dialog consult PPMS service note 1096 304 4 Make sure that an Extended Purge was performed at the end of the Sample Install wizard 1f measurements are being made at low temperatures This will prevent the formation of ice on the bearing surfaces A test for roughness in the bearings is performing the Motor Friction Scan on the Advanced tab of the VSM Control Center Typical hysteresis with a sample rod inserted is 10 20 mA 7 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 7 Se
141. sample and synchronous detection of the voltage induced in the coilset by the magnetized sample In preparation for the measurement you will use the automated VSM Install Remove Sample Wizard to install the sample After that the VSM application software completely automates the next steps which include centering the sample setting measurement parameters and setting up measurement command files as well as operations that are more advanced The measurement process and use of the software are explained in the following subsections Important Before you attempt to begin the measurement process verify that the VSM option and the application software have been installed Chapter 2 and the sample has been mounted on the sample holder Chapter 3 4 2 1 Sample Centering Accurate VSM measurements require that the system oscillate the sample in the center of the coil pair see Figure 5 3 and that the centering position be kept stable to within about 0 1 mm at the center of the pickup coils The 0 1 mm stability is maintained by periodic touchdown operations that adjust for changes in the sample position Quantum Design VSM Option User s Manual 1096 100 Rev BO 4 1 February 2011 Section 4 2 Chapter 4 1BOverview of VSM Measurements Taking VSM Measurements 4 2 1 1 THE TOUCHDOWN OPERATION Automatic sample centering is accomplished with the touchdown operation To perform a touchdown operation the linear motor transport lowers the sa
142. scillation amplitude of the sample rod In addition use of this location exposes the sample to minimal variations in applied magnetic field because the sample is only moved 5 mm during a touchdown operation Quantum Design VSM Option User s Manual 1096 100 Rev BO 3 3 February 2011 Section 3 3 Chapter 3 Mounting Samples Sample Preparation and Mounting 3 3 2 VSM Sample Mounting Techniques Application Note 1096 306 The techniques being illustrated will apply to the SQUID VSM PPMS VSM and VersaLab cryogen free VSM systems Quantum Design provides the selected sample holders The materials for securing the sample to the holders are not included with the installation Due to high accelerations in VSM measurements secure sample mounting is more challenging than in most other measurements Loosely mounted samples will result in noise in the moment measurement see app note 1096 303 and 1500 009 on the Quantum Design website Axial and radial sample positioning error introduces inaccuracy of the reported moment see app note 1500 010 Also a sample geometry influences accuracy of the reported moment see app note 1500 015 Keep the sample length less than 5 mm to maintain the accuracy of the point source dipole approximation 1 The sample holders supplied by Quantum Design are designed to fit on the mounting station The total length of the holder and exact location of the sample are better defined by using the mounting station While
143. sino pee ec eeu od cio 6 4 The immediate mode VSM Center Sample popup eee 6 5 The immediate mode VSM Datafile Comment popup eene 6 5 Install tab in the VSM Control Center esee rennen 6 5 Data File tab in the VSM Control Center 6 6 Recording sample properties essere menn nnne 6 6 Sample tab in the VSM Control Center essen 6 7 Advanced tab in the VSM Control Center eseeeeeeeeeeeeeen 6 7 VSM Measurement dialog and the Settings tab see 6 8 Centering tab in the VSM Measurement dialog eee 6 9 Advanced tab in the VSM Measurement dialog seeeeeeeeeeee 6 10 Data logging dialog for selecting additional types of data to be collected 6 11 Sequence mode VSM Center Sample command VSM Center Sample Sequence POPUD ce en EEEE Eei tener terere betae esee ete esie t e ge ep eere ep epe e e eate a 6 12 Setup tab of the sequence mode VSM Moment versus Field dialog 6 13 Advanced tab of the sequence mode VSM Moment versus Field dialog 6 13 Field Sequence section of the VSM Moment vs Field Setup tab Start End Quadrant de selected aee ete ses i ette eee Pee de Cua ee bak ads sob eaae ed 6 14 Field Sequence section of VSM Moment vs Field Setup tab Start End Ouadrant selected 5 5 ee RR een e D re EH ee eet Ds 6 14 Field Control section of V
144. standard error are both less than 0 5 of the sample moment E e a E IJ 3G 5 amp z The noisy data is explained by the fact that the sample was not moving sinusoidally with the motor but was instead rattling around in the sample holder A significant quadrature component arose because the loose sample lagged behind the motion of the motor M Std Err emu Temperature K Figure 7 4 Magnetization vs temperature data for nickel with sample rattling in the sample holder below 290 K Differential thermal contraction of materials is a common cause of loose joints between parts and it could explain why the noise in this data only appeared at temperatures below 290 K Quantum Design VSM Option User s Manual 1096 100 Rev BO 7 7 February 2011 Section 7 6 Chapter 7 Performing VSM Measurements in PPMS Troubleshooting High Field 14T or Higher Magnets Figure 7 5 is a photograph of an oscilloscope trace of the signal for the same sample used above The signal was taken from the BNC monitor MONITOR JB 2 which is located on the front panel of the VSM CM B module during the measurement Note the jagged distortion of the signal which appears strongest during a particular part of the cycle Figure 7 5 Oscilliscope trace of 40 Hz coilset signal measured at the BNC on the VSM module Note the jagged distortion of the signal which would be smooth and sinusoidal for a well mounted sample The following sugg
145. t box The text will be appended to the currently open VSM data file in the Comment column first column SM Center Sample ni x VSM Datafile Comment loj x Press Center to perform tourchdown operation Text to Append to center sample in coilset Close Help Close Help Figure 6 8 The immediate mode VSM Datafile Figure 6 7 The immediate mode VSM Center Sample popup Comment popup VSM Control Center The VSM Control Center opens within the MultiVu window as soon as you activate the VSM option and application software Figure 6 9 shows the VSM Control Center and the commands dialogs tabs buttons and software prompts that organize measurement related activities making it easy for you to perform basic operations e g create data files install samples and set up and initiate immediate mode measurements 6 4 1 VSM Control Center Components 6 4 1 1 INSTALL TAB lox Install Data File Sample Advanced Chamber Status 1 90K Stable Purged and sealed Install Remove Configure VSM Sample System Status Measure Help VSM Ready Figure 6 9 Install tab in the VSM Control Center Quantum Design VSM Option User s Manual 1096 100 Rev BO 6 5 February 2011 Section 6 4 Chapter 6 VSM Control Center VSM Software 6 6 The Install tab provides access to two wizards o Install Remove Sample guides the user through installation of a sample into the VSM measurement spac
146. ta file is designated the SHE Measure Hel measurement data will be written to the file VSM Ready Data VSMdefault DAT Figure 6 10 Data File tab in the VSM Control Center Creating a new data file will prompt the user to enter sample properties as shown in Figure 6 11 This information recorded in the header of the data file is for information only and is not used in calculating the reported magnetic moment SM Sample Properties X 2 Enter Sample Properties Material Titanium oxide Comment stock sample 1 Additional Descriptive Comments Mass 001 mg Size Volume mm Shape iregular Molecular Tr Weight OK Hel B Figure 6 11 Recording sample properties VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 6 Section 6 4 VSM Software VSM Control Center 6 4 1 3 SAMPLE TAB The Sample tab Figure 6 12 is a read only status display that shows the sample properties e g material comments mass and volume for the active output data file The information in the Sample tab originates from your entries in the VSM Sample Properties dialog which are stored in the header of the output data file If you select a pre existing file to which you want data appended and bring the Sample tab forward the information in the Sample dialog will reflect the entries in the header of the pre existing file SM SIM new vsm1 dat loj x Install Data File Sample
147. that are in effect Normally you will not need to adjust these settings It is recommended to use touchdown centering to ensure the sample remains centered in the coil set See the discussion in Sec 7 4 regarding artifacts that can arise when No Automatic Centering is selected VSM Measurement Se x Settings Centering Advanced Last Measurement Do Touchdown Centering Tempeaue K Delta Time o mna ied De Delta Field o Oe Moment 7 ecu DM Moment m Temperatura ut E Std Emo emu No Automatic Centering Start Pause Close Help Figure 6 15 Centering tab in the VSM Measurement dialog Touchdown operations will occur when any one of the monitors time field or temperature has been exceeded The default parameters of Delta Time 10 minutes and Delta Temperature 10 K will be sufficient for most cases Selecting zero 0 for any of the monitors will turn it off For instance Delta Field 0 should be used for all systems except the 16 tesla PPMS it is provided because the stray field of the main magnet can slightly pull on the motor and change the operating height of the sample Touchdowns result in a approximately 20 second interruption in measurements If this is unacceptable in your measurements then centering can be triggered explicitly by selecting Measure gt gt VSM Center Sample or using the Center Sample sequence command 6 4 2 5 VSM MEASUREMENT DIALOG ADVANCED TAB The A
148. the VSM application software on the computer PC via the CAN bus connector on the back panel of the module See Appendix A for a detailed description of the functions of this module Figure 5 11 Model CM A VSM motor module 4101 100 5 5 4 Model CM B VSM Detection Module Figure 5 12 shows the Model CM B 4101 150 which performs the synchronous detection or ock in operation for the VSM option The reference position signal comes from the Model CM A VSM motor module via the VSM motor sync cable the induced voltage signal from the coilset puck comes via the preamp cable assembly All configuration and control of this module is handled through the VSM application software on the computer PC via the CAN bus connector on the back panel of the module Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 9 February 2011 Section 5 5 Chapter 5 VSM Electronics VSM Hardware See Appendix B for a detailed description of the functions of this module Figure 5 12 Model CM B VSM detection module 4101 150 5 5 5 Model 1000 Modular Control System PPMS ONLY The Model 1000 modular control system 4100 001 is a general purpose chassis Figure 5 13 that houses cools and provides power to both the Model CM A VSM motor module and the Model CM B VSM detection module The Model 1000 can accommodate up to four additional modules for other PPMS options The backplane provides connections for power as well as a CAN bas
149. the sample The sensitivity of the VSM coils is not significantly affected by large magnetic fields so the VSM can perform sensitive measurements up to the maximum field available from your magnet The VSM detection coil is inserted into the sample chamber by using the standard sample interface design This procedure will make it easy to reconfigure the VSM option with alternate pickup coil designs in the future You will find that you can change the pickup coil configuration as easily as you can change a puck You will find it easy to activate and deactivate the VSM option on your system just like the other options The modularity of the design enables you to perform successive types of measurement with little additional effort For example you could follow state of the art VSM measurements with heat capacity measurements by inserting a different puck or probe 1 3 Theory of Operation The basic principle of operation for a vibrating sample magnetometer is that a changing magnetic flux will induce a voltage in a pickup coil The time dependent induced voltage 1s given by the following equation dd V coil dt 12 E X dz JA dt In equation 1 1 is the magnetic flux enclosed by the pickup coil z is the vertical position of the sample with respect to the coil and t 1s time For a sinusoidally oscillating sample position the voltage is based on the following equation V coi 2afCmAsin 2aft 1 2 In equation 1 2 C is
150. ther the suspension mechanism is functioning Quantum Design VSM Option User s Manual 1096 100 Rev BO 5 1 February 2011 Section 5 2 Chapter 5 VSM Hardware Components VSM Hardware correctly by gently tapping the top of the sample rod at the sample access port during sample loading A mechanism that is working correctly will oscillate for at least 5 seconds The transport is shipped from the factory with the shipping plug installed to prevent oscillation of the motor suspension mechanism Before using the equipment you must remove the shipping plug and install the extender tube flange A window in the front side of the linear motor transport opposite the electrical connector displays the location of the armature the moving section of the motor transport When you are installing or removing samples you will be able to see an indicator pin at the top of the window The indicator pin will be at the top of the window when the system is in the load position The indicator pin will be at the bottom of the window which is the shutdown position only when the sample rod has been removed and the linear motor transport has been shut down During VSM operations the indicator pin will vibrate rapidly 1 4 mm peak to peak amplitude at 40 Hz between the load and shutdown positions Important The sample will be subject to vertical magnetic fields of up to approximately 200 gauss when it passes through the head If this is unacceptable for y
151. ton in the PPMS Data Logging section opens the PPMS dialog Figure 6 17 so that you can select additional system information to be sent to the output data file For more information on Data Logging see Section 6 4 2 5 6 8 3 4 ADVANCED SETTINGS Advanced Settings IV Require Sweep Mode For Continuous Acquisition The Advanced Settings subsection Figure 6 27 contains settings that are rarely Wat Times 5 ee needed but they can provide extra control Restore X Defaul over your measurements hne Z haat p Excitation Parameters Quantum Design Require Sweep Mode for Continuous Acquisition When you set Data Acquisition to Continuous Measurement Section 6 8 2 3 the system automatically uses Sweep Mode and the check box next to Require Sweep Mode For Continuous Acquisition will be selected Peak Amplitude a mm Frequency o x Hz Maximum Acceleration i233 m sec Maximum Moment 10 46875 emu Figure 6 27 Advanced Settings Advanced tab Require sweep Wait Time and Approach Mode settings VSM Option User s Manual 1096 100 Rev BO 6 17 February 2011 Section 6 9 Chapter 6 Sequence Mode VSM Moment vs Temp Command VSM Software Although you can clear the check box and select the Driven at each field or Persistent at each field mode during continuous measurements be aware that these modes might increase the noise and introduce artifacts into your data Note If you measure continuously wh
152. tor Module Figure A 1 Model CM A VSM motor module 4101 100 A 2 1 Functional Block Diagram STEPPER MOTOR CONNECTOR Figure A 2 Abridged functional block diagram of Model CM A VSM motor module specifications A 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix A Section A 3 Model CM A VSM Motor Module 2BModel CM A VSM Motor Module Front Panel A 2 2 J Specifications Table A 1 Electrical specifications tor Model CM A VSM motor module Drive Current Limit 3A Drive Voltage Compliance Limit 20 V peak Encoder Range 32 bit Supply Voltage 24 V DC A 3 Model CM A VSM Motor Module Front Panel A 3 1 Indicator LEDs The front panel of the Model CM A VSM motor module has two LEDs in the top left as shown in Figure A 1 The PWR LED indicates the power on status of the module The COP CANopen Protocol LED indicates the status of the CAN network controller Table A 2 outlines the LED states and provides solutions in the event of a problem Important The error information in Table A 2 refers to situations that persist for longer than about 15 seconds Typically when the module is powered on the LEDs may briefly flash red before they turn green This is a normal part of the startup or reset sequence Table A 2 LED guide for Model CM A VSM motor module LED COLOR STATUS MEANING AND OR SOLUTION PWR Green On The processor is r
153. ts 4 3 2 Activate the VSM Option and Control Center 1 To start the VSM application and open the VSM Control Center select Utilities gt gt Activate Option in the MultiVu window 2 At this time the system also will perform a Home operation to determine the full range of travel for the sample transport by touching down and then going to the load top position 4 3 3 Install the Sample 1 In the Install tab of the VSM Control Center click on the Install Remove Sample button 2 Click on the Open Chamber button below the Instructions area The wizard will bring the sample chamber to room temperature vent the chamber and move the transport to the load position and the Instructions area will show the status of these processes 3 When the Instructions area indicates that the chamber has been flooded and the transport is in the load position use the sequence outlined below to install the sample rod and sample e Ifyou have not already measured your sample offset position use the sample mounting station to obtain the sample offset from the end of the sample holder see Section 4 3 1 e Attach the sample holder to the sample rod e Remove the cap from the top of the VSM linear motor transport e Insert the sample rod with the attached sample holder into the sample access port until the magnetic lock at the top of the sample rod engages the magnetic lock ring in the linear motor transport Verify that the magnetic lock has engaged t
154. uantum Design VSM Option User s Manual 1096 100 Rev BO 2 3 February 2011 Section 2 2 Chapter 2 1BInitial Installation of the Hardware and Software Installing and Removing the VSM Option 1 Verify that the power cable has been connected to the Model 1000 and it has been turned on 2 Verify that the power LED on the front of the Model 1000 is lit green 3 Verify that the Model 1000 is connected to the CAN adapter on the PC via the CAN network cable 2 2 2 Prepare the System for Option Installation To prepare the System for installation of the VSM option you will use the MultiVu application to warm the sample chamber to 300K set the magnetic field to zero 0 Oe and vent the sample chamber Then you will remove any sample puck or option that is currently installed in the chamber When you do this be sure to remove the standard centering ring from the chamber opening the VSM has a custom designed centering ring 1 Set the system temperature to 300 K 2 Set the field to zero 0 Oe WARNING Verify that there are no nearby sources of magnetic field e g NMR or other laboratory magnets before attempting to install or remove the linear motor transport as explained in Section 1 4 1 3 Vent the sample chamber 4 Remove any sample puck or option that is installed in the sample chamber 5 Remove the standard centering ring or any other hardware that is present from the top flange of the system
155. uired CAN network signals to communicate with the module Quantum Design VSM Option User s Manual 1096 100 Rev BO B 1 February 2011 Section B 2 Appendix B 1BFunctional Overview Model CM B VSM Detection Module s QUANTUM DESIGN VSM MODULE MODEL CM E Figure B 1 Model CM B VSM detection module 4101 150 B 2 1 Functional Block Diagram THERMOMETER DAC 16 bit Figure B 2 Abridged functional block diagram of the Model CM B VSM detection module B 2 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Appendix B Model CM B VSM Detection Module B 2 2 B 3 B 3 1 Quantum Design Section B 3 2BModel CM B Detection Module Front Panel Specifications Table B 1 Electrical specifications for the Model CM B VSM detection module Input Ranges from preamp 5 V 0 5 V 50 mV 5 mV Thermometer Current Ranges 0 02 mA 0 5 mA Thermometer Voltage Range 10 mV Thermometer Sample Rate 14 Hz Thermometer Resistance Range 20 to 200 000 ohms Supply Voltage 24 V DC Model CM B Detection Module Front Panel Indicator LEDs The front panel of the Model CM B detection module has two LEDs in the top left as shown in Figure B 1 The PWR LED indicates the power on status of the module The COP CANopen Protocol LED indicates the status of the CAN network controller Table B 2 outlines the LED states and provides solutions in the event o
156. unning with no errors normal Red Flashing Errors were encountered during the self test The flashing sequence can be used to determine the cause of the failure COP Green On CAN status is operational normal Flashing CAN status is pre operational Verify that cable is connected to PC Red On or Error on the CAN bus Contact flashing Quantum Design for assistance If you are unable to achieve operation with both LEDs green please contact Quantum Design for assistance Quantum Design VSM Option User s Manual 1096 100 Rev BO A 3 February 2011 Section A 3 Appendix A 2BModel CM A VSM Motor Module Front Panel Model CM A VSM Motor Module A 3 2 Connectors and Pinout Tables A 3 2 1 JA 1 SERVO CONNECTOR This connector is used to provide the current drive to the motor and read back the position information from the encoder This connector also supports serial communication to logic associated with the motor e g serial ROM for storing calibration or configuration information about the motor OOOOOOOOO O00000000 nO OO 000000 Figure A 3 JA 1 Servo connector for the Model CM A VSM motor module Table A 3 JA 1 Servo connector for the Model CM A VSM motor module PIN FUNCTION 1 Motor 2 4
157. ure7 3 Showing artifact in reported moment due to errors in vertical centering Thus the following points should be kept in mind whenever making VSM measurements and especially when temperature dependent measurements are being performed 1 When making temperature scans touch down every 10 K 2 When at stable temperature touchdown every 10 minutes unless you are confident that the sample chamber thermal profile is stable Keep in mind that this will be affected by any temperature changes within the last 4 hours 3 Try to mount your sample so that the reported moment is not a strong function of vertical position see ideal sample centering scan in Figure 7 2 If the touchdown centering operation is not appropriate to your sample it is possible to activate an advanced centering option which allows you within a measurement sequence to re center the sample by scanning or by setting an absolute motor position Keep in mind that there are more risks involved when automating the centering scan or when setting the absolute motor position that can result in damage to the sample sample rod or even the motor Please contact apps qdusa com for more information if you would like to access this advanced centering feature 7 6 VSM Option User s Manual 1096 100 Rev BO Quantum Design February 2011 Chapter 7 Section 7 5 Troubleshooting Mounting Samples Loosely Causes Moment Noise 7 5 Mounting Samples Loosely Causes Moment Noise VSM
158. varnish should prevent the sample from becoming loose A long 10 cm Quantalloy support piece can be wedged into place and the films attached to this surface with glue It is more easily cleaned disposable and will not magnetically contaminate the brass trough The short 4 mm tall Quantalloy coupon is useful for sensitive oxygen leak tests near 50 K by providing a large surface area point source dipole and diamagnetic signal at 1 Tesla After the quartz sample holder breaks the brass trough can be made to accommodate the inverted shape The quartz provides a magnetically clean surface area 3 For films perpendicular to field an effective technique uses quartz braces that snap into the brass trough The length of the brace will depend on the system with the SQUID VSM needing the longest to minimize end effect issues The braces must come into contact with both sides of the film to hold it securely If contact with the surface is not allowed glue sample to one end and put second quartz brace as close as possible to minimize gap signal Matched sets of fixed angle quartz pieces with values such as 22 5 30 45 and 60 degrees can provide a useful data set for verification of rotator experiments While the press fit of metal on quartz should be good over the range of 1 8 K to 400 K it is prudent to secure ends of quartz pieces with glue If the sample signal is comparable or smaller than the brass trough one should use a quartz paddle If the film i
159. ven sample holder is not specifically made for low temperature operation While tests show no harm in thermal cycling to 2 K there is always a risk of exposing a weakness in the wiring of the heater stick through this procedure The mounting technique on a blank stick would hold to the lowest temperature This Zircar cement is also a way to avoid using organic solvent based materials The water based gradual drying process may be appropriate for incorporating powders from biological or other exotic systems Removal of the sample usually involves a thinly wedged stick providing lateral force on the sample The cement cracks easily While water or isopropanol IPA may aid in the removal of the excess the main goal is to not hurt the laminate coating the patterned heater wires No sharp metal objects try disposable Teflon tweezers or thin flat wooden surfaces Use a microscope to see detail of interface C Tape is a simple and effective method for securing to the quartz rod It will prevent the sample from being lost during the measurement The background can be reasonably small if the mass is symmetrical about the sample Keeping the tape clean from magnetic dust around the lab is the primary concern 1 Kapton tape is commonly used at low temperatures and is available from Quantum Design It retains properties over entire range of 1 8 K to 400 K As a point source may show 10 emu ferro magnetic signature at room temperature Like with a straw if

Vibrating Sample Magnetometer - Materials Research Facilities

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