Lake Shore 74046 User manual

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Methods and apparatus disclosed and described herein have been developed solely on company funds of
Lake Shore Cryotronics, Inc. No government or other contractual support or relationship whatsoever has existed
which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics, Inc. in these developments.
Methods and apparatus disclosed herein may be subject to U.S. Patents existing or applied for.
Lake Shore Cryotronics, Inc. reserves the right to add, improve, modify, or withdraw functions, design modifications,
or products at any time without notice. Lake Shore shall not be liable for errors contained herein or for incidental or
consequential damages in connection with furnishing, performance, or use of this material.
Rev. 1.0 P/N 119-605 15 July 2010
Manual Addendum to the
7400 Series VSM
Model
74046
Magnetoresistance
Insert Probe Option
Lake Shore Cryotronics, Inc.
575 McCorkle Blvd.
Westerville, Ohio 43082-8888 USA
[e-mail]
[e-mail]
www.lakeshore.com
Fax: [phone]
Telephone: [phone]

Model 74046 Magnetoresistance Insert Probe Option
LIMITED WARRANTY STATEMENT
WARRANTY PERIOD: ONE (1) YEAR
1.Lake Shore warrants that this Lake Shore product (the "Product")
will be free from defects in materials and workmanship for the War-
ranty Period specified above (the "Warranty Period"). If Lake Shore
receives notice of any such defects during the Warranty Period and
the Product is shipped freight prepaid, Lake Shore will, at its option,
either repair or replace the Product if it is so defective without charge
to the owner for parts, service labor or associated customary return
shipping cost. Any such replacement for the Product may be either
new or equivalent in performance to new. Replacement or repaired
parts will be warranted for only the unexpired portion of the original
warranty or 90 days (whichever is greater).
2.Lake Shore warrants the Product only if it has been sold by an autho-
rized Lake Shore employee, sales representative, dealer or original
equipment manufacturer (OEM).
3.The Product may contain remanufactured parts equivalent to new
in performance or may have been subject to incidental use.
4.The Warranty Period begins on the date of delivery of the Product or
later on the date of installation of the Product if the Product is
installed by Lake Shore, provided that if you schedule or delay the Lake
Shore installation for more than 30 days after delivery the Warranty
Period begins on the 31st day after delivery.
5.This limited warranty does not apply to defects in the Product
resulting from (a) improper or inadequate maintenance, repair or cal-
ibration, (b) fuses, software and non-rechargeable batteries, (c) soft-
ware, interfacing, parts or other supplies not furnished by Lake Shore,
(d) unauthorized modification or misuse, (e) operation outside of the
published specifications or (f) improper site preparation or mainte-
nance.
6. TO THE EXTENT ALLOWED BY APPLICABLE LAW, THE ABOVE WAR-
RANTIES ARE EXCLUSIVE AND NO OTHER WARRANTY OR CONDITION,
WHETHER WRITTEN OR ORAL, IS EXPRESSED OR IMPLIED. LAKE
SHORE SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OR CON-
DITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY AND/OR FIT-
NESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE PRODUCT.
Some countries, states or provinces do not allow limitations on an
implied warranty, so the above limitation or exclusion might not
apply to you. This warranty gives you specific legal rights and you
might also have other rights that vary from country to country, state
to state or province to province.
7.TO THE EXTENT ALLOWED BY APPLICABLE LAW, THE REMEDIES IN
THIS WARRANTY STATEMENT ARE YOUR SOLE AND EXCLUSIVE REME-
DIES.
8.EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW, IN NO
EVENT WILL LAKE SHORE OR ANY OF ITS SUBSIDIARIES, AFFILIATES OR
SUPPLIERS BE LIABLE FOR DIRECT, SPECIAL, INCIDENTAL, CONSE-
QUENTIAL OR OTHER DAMAGES (INCLUDING LOST PROFIT, LOST DATA
OR DOWNTIME COSTS) ARISING OUT OF THE USE, INABILITY TO USE
OR RESULT OF USE OF THE PRODUCT, WHETHER BASED IN WAR-
RANTY, CONTRACT, TORT OR OTHER LEGAL THEORY, AND WHETHER
OR NOT LAKE SHORE HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES. Your use of the Product is entirely at your own risk.
Some countries, states and provinces do not allow the exclusion of lia-
bility for incidental or consequential damages,sothe above limitation
may not apply to you.
9.EXCEPT TO THE EXTENT ALLOWED BY APPLICABLE LAW, THE TERMS
OF THIS LIMITED WARRANTY STATEMENTDO NOT EXCLUDE, RESTRICT
OR MODIFY, AND ARE IN ADDITION TO, THE MANDATORY STATUTORY
RIGHTS APPLICABLE TO THE SALE OF THE PRODUCT TO YOU.
CERTIFICATION
Lake Shore certifies that this product has been inspected and tested in
accordance with its published specifications and that this product
met its published specifications at the time ofshipment. The accuracy
and calibration of this product at the time of shipment are traceable
to the United States National Institute of Standards and Technology
(NIST); formerly known as the National Bureau of Standards (NBS).
TRADEMARK ACKNOWLEDGMENT
Many manufacturers and sellers claim designations used to distin-
guish their products astrademarks. Where those designations appear
in this manual and Lake Shore was aware of a trademark claim, they
appear with initial capital letters and the ™ or ® symbol.
Kapton® is a trademarks of DuPont De Nemours.
Microsoft Windows®, and Excel® are registered trademarks of
Microsoft Corporation in the United States and other countries.
Copyright 2010 Lake Shore Cryotronics, Inc. All rights reserved. No portion of this manual addendum may be
reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without the express written permission of Lake Shore.

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Table of Contents
1.0 Introduction 1.1 Model 74046 Magnetoresistance Insert Option Part List . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 Software
Installation
2.1 MR Measurement System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1.1 Page One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.1.2 Page Two . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.3 Page Three . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.4 Page Four . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.5 Page Five . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.6 Page Six . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.7 Page Eight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.8 Install Software Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.0 MR
Operation
3.1 Switching from VSM to MR Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Sample Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Installing the MR Insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3.1 Attach the Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3.2 Install and Adjust the MR Head Lock (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3.3 Install the MR Insert Probe Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3.4 MR Software Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.4.1 Calibrating the Gaussmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.2 Creating a Sample Definition File (*.Mrs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.3 Creating a Measurement Setup File (*.Mrm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4.3.1 Control Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.4.3.1.1 Go to Angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.4.3.1.2 Go to Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.4.3.1.3 Go to Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.4.3.1.4 Wait Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.4.3.1.5 Shut Down Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4.3.2 Experiment Step: Contact Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.4.3.3 Experiment Step: IV Contact Checking Measurement . . . . . . . . . . . . . . . . . 16
3.4.3.4 Experiment Step: R Vs. Field Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.4.3.4.1 Variable Field Measurement–Field Profile Dialog Box . . . . . .17
3.4.3.4.2 Variable Field Measurement —-
Measurement and Analysis Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.4.3.5 Experiment Step: R vs.Temperature Measurement . . . . . . . . . . . . . . . . . . .21
3.4.3.6 Experiment Step: R vs. Angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.4.4 Executing a Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.4.5 Displaying Data From a Measurement Results File . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.4.6 Using Manual Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.4.6.1 Manual Field Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
3.4.6.2 Manual Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.4.7 Operating a Temperature Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

ii Model 74046 Magnetoresistance Insert Option
Model 74046 MR Insert Option
4.0 MR
Measurements
4.1 Sample Size and Pin Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.1 Correcting a Skew in the MR Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.1.1 Testing for Skew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.1.2 Re-Seating Probe Points with the Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.1.1.3 Post-Processing Data Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2 Maximizing Repeatability of R Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.1 Handling the Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.2 Constructing a Sample Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.3 Pin Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.0Maintenance 5.1 Disassembling the MR Insert Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.2 Replace Internal Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.2.1 Replace Ceramic Holder and Pin Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.2.2 Solder the Probe Pins to the PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.3 Reassemble the MR Insert Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.3.1 Reassemble the MR Internal Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.3.2 Reassemble the Top Cover to the Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

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Model 74046 Magnetoresistance Insert Probe Option
7400 Series VSM Hardware and Software Manual Addendum
1.0 Introduction The Model 74046 magnetoresistance insert probe option for the 7400 Series VSM
provides a method to measure magnetoresistance (MR) effects with a small sample
geometry. Magnetoresistance can be measured both at room temperature and at
variable temperatures when placed within the sample bore of a Lake Shore VSM
temperature appliance such as a Model 74034 oven or Model 74018 cryostat. The
MR insert itself works in conjunction with a Keithley Model 2400 current source,
Lake Shore Model 775 matrix switch, Lake Shore Model 736 VSM controller and
Lake Shore electromagnet and power supply to comprise a versatile MR sample test
system.
1.1 Model 74046
Magnetoresistance
Insert Option Part
List
1.2 Specifications
Part Number Description Contents
651-066 Model 74046 MR kit
MR insert probe
USB key
MR spares kit
2 PCBs
8 MR spare points
7410 extension rod
(for 7410 systems only)
Model 74046 accessories kit
MR head lock kit
Model 74046 manual
Model 74046 software CD
651-065 Model 74046 MR holder —
Keithley 2400 with DB-9
interlock connector —
Model 775 matrix switch —
651-061 MR adapter box MR adapter box
4-wire I-V cable
119-605 Model 74046 Manual Addendum
to the 7400 Series VSM —
TABLE 1-1 Model 74046 MR insert probe option part list
Sample cross-section 4.5 mm × 4.5 mm (0.178 in × 0.178 in)
Sample height, maximum ~3.2 mm (~0.125 in)
Pin-to-pin spacing 0.9 mm (0.036 in)
Total pin spacing 2.7 mm (0.108 in)
Current 1 µA – 100 mA
Compliance voltage 5 V
Contact formation User adjustable time, current, and voltage
Nominal resistance range 50 m)– 10 M)
VSM compatibility 7400 Series
TABLE 1-2 Model 74046 MR insert probe option specifications

2Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
2.0 Software
Installation
Follow these instructions to install the software.
1. Turn on the PC and rack console.
2. Insert the MR disk into the CD Rom drive and run the software installation file,
“LakeShoreMRV2.X Setup.EXE”.
2.1 MR
Measurement
System
Configuration
At the end of the software installation, the MR Measurement System Configuration
program will start. This program configures the MR software for use with your
hardware. Follow these instructions to configure the MR software.
2.1.1 Page One
DSelect Setup, run and view files.
FIGURE 1 Page one

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2.1.2 Page Two
KI 2400 sourcemeter setup:
DCommunication: Keithley Model 2400 IEEE address—leave at default
DProtection: set the KI 2400 measurement compliance voltage to 5 V
DCustom filter time: the following KI 2400 instrument settings are used when cus-
tom filter time is chosen in the system configuration.
Measurement speed (NPLC): enter 1. This sets the integration time of the A/D
converter in number of power line cycles.
Auto zero every conversion: click to clear this setting. This setting forces the
instrument to verify the zero of the A/D converter before each measurement is
made, minimizing drift on long measurements.
Use filter: select this setting to use the filter built into the KI 2400 to reduce noise
in voltage readings. This may reduce the bandwidth of the voltage
measurements.
FIGURE 2 Page two

4Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
2.1.3 Page Three
DSwitching: leave at default
DVSM head: select the VSM head drive model number
DAuto rotation option: select this option if present
Communication: Select COM 1
Logging: click to clear this setting
FIGURE 3 Page three

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2.1.4 Page Four
DSelect your electromagnet model and polecap diameter
2.1.5 Page Five
DSelect your magnet power supply model
FIGURE 4 Page four
FIGURE 5 Page five

6Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
2.1.6 Page Six
DField control setup parameters: select Accept Defaults
2.1.7 Page Eight
DTemperature option: select No Temperature Option
FIGURE 6 Page six
FIGURE 7 Page eight

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2.1.8 Install Software
Key
The MR software may be run on multiple computers to view and manipulate results
files at your desk, for example. But data acquisition may only occur on the MR system
PC with the software key installed. The software key is a small, light green USB device,
labeled # 672-676, SOFTWARE KEY. Place it into an available USB slot in the PC. This
software key will remain attached to the PC. It is reqired to run an experiment file
with the MR software.

8Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
3.0 MR Operation This section includes basic procedures for daily operation of the MR insert.
3.1 Switching
from VSM to MR
Mode
1. From the VSM software, select Current mode and ramp the field to zero.
2. Exit the VSM software.
3. Remove the sample tail from the VSM head (see VSM manual for removing the
sample tail).
4. Start the MR software from the MR Measurement icon on the Windows™
desktop. If any errors in the system configuration are detected, it will be noted
onscreen and the system will install in demo mode without software acquisition
capability. The problem will be noted in the system log of the Main menu screen.
Once the problem is corrected, exit and restart the software.
5. Start the power supply
6. Install the MR insert on the VSM head (see section 3.3 to install the MR insert).
3.2 Sample
Exchange
When using a variable temperature option, sample exchange must be performed with the
variable temperature option at room temperature to avoid sample thermal shock.
1. Decouple the MR insert from the VSM head.
a. Unscrew the VSM head's captive knurled coupling nut from the MR insert.
b. If you are using a variable temperature option, raise the captive knurled
coupling nut and slide the VSM head rearward.
2. Prepare the MR Insert.
a. Place MR insert on MR holder.
b. Finger tighten the white nylon screw on the holder to secure the insert in the
holder; do not over tighten as this can damage the insert tube (FIGURE 10).
c. At the top of the MR body, raise both MR lock levers and lock in upper position
(FIGURE 8).
Always use both lock levers when moving the pins up or down.
FIGURE 8 Raise both lock levers

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3. Install the sample with the tweezers provided in the MR insert kit. Position the
sample the same way each time for best data reproducibility (see section 4.2 for
more information about measurement repeatability).
Use this procedure to center the sample.
a. Use the tweezers to grip the sides of the sample.
b. Place the sample into the sample access near the bottom of the insert tube
(FIGURE 9). There is a raised rear stop in the back of the sample access which
determines the depth to place your sample.
c. Use the tweezers’ angled sides to center the sample with respect to the
sample access opening. This also centers the sample with respect to the
contact pins. You may need to lower the insert pins using the lock levers to
determine whether you have centered the sample under the pins.
d. Install the MR insert onto the VSM head using the procedures in section 3.3.
e. Adjust MR lock so DC level is within ±20% .
3.3 Installing the
MR Insert
To install the MR insert, you will first need to attach the cabling, install and adjust the
MR head lock, and then install the MR insert.
When not installed on the VSM head, the MR insert may be placed in the MR holder for
storage, sample exchange, etc. Finger tighten the white nylon screw to secure the insert
in the holder; do not over tighten as this can damage the insert tube (FIGURE 10).
FIGURE 9 Sample access in the insert tube
FIGURE 10 Left: Place the MR insert into the holder; Right: Finger tighten the white nylon screw

10 Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
3.3.1 Attach the Cables 1. Locate the MR console cable. It is the grey cable with an 8-pin circular bayonet
connector that exits from the rear of the VSM console, where the other end is
permanently attached to the blue MR adaptor box. This cable transmits the
current and voltage for the 4-wire resistance measurement.
2. Attach the MR console cable to the 8-pin connector of the MR insert cable (the
cable wired to the MR insert body).
Early versions of the MR insert utilized a 4-pin connector. The oven cable has a similar 4-
pin connector. But the oven cable will have an outer mesh covering a cable composed of
both a small brown TC wire pair and a grey heater cable that terminates at the Model 340
controller's TC and heater connections. Do not confuse the two cables, as damage may
occur if you make the wrong connection.
3.3.2 Install and Adjust
the MR Head Lock
(Optional)
The 7400 Series VSM heads are equipped with DC, Z-height compensation. This DC
feedback signal indicates the height of the VSM head suspension relative to a nominal
0 reference Z height. If the suspension drifts up or down, the system automatically
compensates for this shift (within it's operating limits). The lock is intended to
manually hold the suspension at this 0 point so that little drag is placed on the VSM
head suspension when using the MR insert. Though the VSM head suspension can
operate without the lock; however, the lock allows the suspension to return to
working range faster.
Use this procedure to install and adjust the MR head lock.
1. Turn on the MR software.
2. From the Main menu, select Measurement, Adjust MR Head Lock. The Adjust
Head Lock dialog box appears (FIGURE 11). Leave the dialog box open.
3. Install the MR headlock:
D For VSM heads with upper Z-adjust knobs: slide the head lock onto the four
rotation adjust screws on the VSM head. Turn the head lock to the left to lock it
into place (you may need to loosen the black nylon thumbscrew to attach the
head lock).
D For VSM heads with lower Z-adjust knobs: slide the head lock onto the VSM
head, and finger tighten the four black nylon thumbscrews so that the head
lock is flush over the bottom of the head.
FIGURE 11 Adjust MR Head Lock dialog box in the MR software

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4. Slowly turn the large black adjust knob (FIGURE 12) at the center of the head lock
and monitor the DC position (FIGURE 11) until it reaches ±0.5 V.
5. Click Close in the Adjust MR Head Lock dialog box to set the DC position.
3.3.3 Install the MR
Insert Probe Option
To install the insert, position the threaded cap on the insert into the captive knurled
coupling nut on the VSM head, and attach it as you would a sample tail (FIGURE 13).
If you are using a temperature option, slide the VSM head forward with the coupling nut
raised to prevent interference between the MR insert and VSM head.
FIGURE 12 Black adjust knob on the head lock
FIGURE 13 MR insert probe option
attached to VSM

12 Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
3.4 MR Software
Operation
The MR Software uses a traditional Windows™ interface, incorporating a main menu,
toolbar, and a status bar. You may create files, save them, and open them in the same
manner as other Windows™ software. At the bottom o f the main software screen is a
status bar. It is divided into four segments.
The first segment denotes status.
D Setup mode: user is manipulating a measurement setup file
D Running: measurement in progress
D Idle: measurement is complete or has been stopped
The second segment denotes the current step of an experiment which is being
executed. The third segment indicates the current field reading, with special symbols
for approaching and settling at field. The fourth segment indicates the current
temperature reading (in temperature mode), with special symbols for approaching
and settling at temperature.
3.4.1 Calibrating the
Gaussmeter
Zero the gaussmeter probe to eliminate any offsets in the probe at zero field. This is
necessary to eliminate gaussmeter offset drift. It is best done at least 15 min after the
Model 736 VSM controller is turned on.
To do this, from the Main menu select Calibration, Gaussmeter Offset Calibration. The
dialog box that appears (FIGURE 14) will give you the remaining instructions to zero
the gaussmeter probe.
When replacing the probe, make sure the Lake Shore logo on the probe faces left
when you are facing the front of the electromagnet.
The gaussmeter probe is fragile. Be careful not to drop the gaussmeter probe or allow it to
impact anything when moving it.
3.4.2 Creating a Sample
Definition File (*.Mrs)
A sample definition file holds basic sample identification information. Sample
dimensions, sample geometry, lot tracking, or other information to identify the
sample can be stored in this file. Since the MR software is not computing any values
based on the sample's dimensions, no dimensional data entry is required, though you
may add it if you wish. The sample definition file is not required for operation. The
system will prompt the user to link a sample definition file prior to measurement
execution. Upon completion of the measurement, that sample definition file will be
linked to the new measurement results file.
If you do not setup a sample definition file, only the filename of the measurement results
file can be used to differentiate samples.
FIGURE 14 Zero Gaussmeter Probe dialog box

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3.4.3 Creating a
Measurement Setup
File (*.Mrm)
A measurement setup file holds a sequence of commands which are executed during
a measurement. These commands are called control steps (section 3.4.3.1) and
experiment steps (section 3.4.3.2 to section 3.4.3.6). A measurement setup file may
hold only one step. However, combining multiple control and experiment steps in a
single measurement setup file allows the user the flexibility to define and execute
comprehensive measurement sequences. Once a measurement setup file is defined,
it can be saved for later recall and execution.
3.4.3.1 Control Steps
Control steps allow the user to perform simple, direct commands. There are several
control steps found in the Main menu under Measurement converter. The control
steps and their purposes are described in section 3.4.3.1.1 to section 3.4.3.1.5.
3.4.3.1.1 Go to Angle
Go to angle rotates the MR assembly to the angle specified. The sample and the
contact pins are rotated together. A VSM autorotation option is required for this
measurement. It is assumed that the user has already performed an auto head
rotation calibration.
1. From the Main menu, select Measurement, Add Measurement, Go to Angle.
2. This dialog box will prompt you to enter the desired angle.
3. Enter the setting and click OK.
4. The go to angle control step is added to the current measurement setup.
3.4.3.1.2 Go to Temperature
Go to temperature executes a temperature change according to the current
temperature control parameters (P,I ramp-rate) as defined in the configuration
utility.
1. From the Main menu, select Measurement, Add Measurement, and Go to
Temperature.
2. This dialog box will prompt you to enter the desired temperature.
3. Enter the setting and click OK. Note the units used.
4. The go to temperature control step is added to the current
measurement setup.
FIGURE 15 Go to Angle dialog box
FIGURE 16 Go to Temperature dialog box

14 Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
3.4.3.1.3 Go to Field
Go to field executes a field change according to the current field control parameters
(P,I ramp-rate) as defined in the configuration utility.
1. From the Main menu, select Measurement, Add Measurement, Go to Field.
2. This dialog box will prompt you to enter the field.
3. Enter the field and click OK.
4. The go to field control step is added to the current measurement setup.
3.4.3.1.4 Wait Time
Wait time executes a delay in the measurement.
1. From the Main menu, select Measurement, Add Measurement, Wait Time.
2. This dialog box will prompt you to enter the wait time.
3. Enter the wait time and click OK.
4. The go to wait time control step is added to the current
measurement setup.
3.4.3.1.5 Shut Down Heater
Shut down heater is often used in conjunction with the go to temperature step. This
type of step forces the system to turn off the temperature device's Loop 1 heater. Loop
2 heaters are not affected.
1. From the Main menu, select Measurement, Add Measurement, Shut Down
Heater.
2. No dialog box is issued. The action is added to the current measurement setup.
FIGURE 17 Go to field dialog box
FIGURE 18 Wait Time dialog box

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3.4.3.2 Experiment Step: Contact Formation
Contact formation is a process that attempts to create ohmic contacts from samples
with oxide barriers or other impediments to good probe point contact. This is
accomplished by placing a voltage across two specific probe points. A DC voltage
source is used for this measurement. Up to 100 V are available with up to 100 mA of
compliance current. Up to 20 V are available with up to 100 mA of compliance
current. N cycles of positive current will be sourced, followed by N cycles of negative
current. This methodology is known to break down oxide layers for certain sample
configurations. Following this process with IV contact checking can verify if the
contacts have been improved.
Use this procedure to include a contact formation experiment to the measurement
setup file.
1. From the Main menu, select Measurement, Add Measurement, Contact
Formation.
2. This dialog box controls the operation of the contact formation process.
D Contacts: choose the pair of contacts to apply the voltage source.
D DC voltage: enter the voltage to be sourced.
D Current limit: enter the compliance current for the voltage source.
D On time: enter the time period that the voltage will be sourced
D Off time: enter the time period that the voltage will be off.
D Cool down time: enter the time period to wait after the contact formation
cycling has completed.
D Number of cycles: enter the number of times that the voltage will be cycled on
and then off.
3. Enter the above parameters and click OK.
4. The contact formation experiment is added to the measurement setup.
FIGURE 19 Contact Formation dialog box

16 Model 74046 Magnetoresistance Insert Probe Option
Model 74046 MR Insert Probe Option
3.4.3.3 Experiment Step: IV Contact Checking Measurement
IV contact checking applies a series of currents across a specific probe point contact
pair, measures the resulting voltages across the pair, and plots the data as a V vs. I
plot. The mathematical correlation of the graphed line determines the quality of the
contacts. A correlation of 0.9999 or higher is indicative of good, ohmic contacts.
Variation from this value is indicative of heating effects, diode effects, or other
imperfections in the contact arrangement. Contact formation may improve the
quality of a contact pair.
Use this procedure to include IV contact checking to the measurement setup file.
1. From the Main menu, select Measurement, Add Measurement, IV Contact
Checking.
2. This dialog box controls the operation of the IV contact checking process.
D Contact pairs: choose the pair of contacts to check.
D Measurement profile
Starting current: minimum current used in the test. Usually, this value is
negative.
Ending current: maximum current used in the test. Usually, this value is
positive, and the same magnitude as the starting current.
D Current step: the increment size of the intermediate current steps.
D Dwell time: time after current is excited prior to data acquisition.
D Filter time: time period that the acquired data is averaged.
3. Enter the above parameters and click OK.
4. The IV contact checking experiment is added to the measurement setup.
3.4.3.4 Experiment Step: R Vs. Field Measurement
This is a traditional MR experiment. This experiment records R vs. field data. Use this
procedure to include R Vs field measurement to the setup file.
1. From the Main menu, select Measurement, Add Measurement, Variable Field
Measurement.
2. The dialog boxes shown in section 3.4.3.4.1 and section 3.4.3.4.2 will control the
operation of this measurement.
FIGURE 20 IV Contact Checking dialog box