中国科学院物理研究所通用实验技术公共课程

中国科学院物理研究所通用实验技术公共课程

《磁性测量》

赵同云磁学国家重点实验室

2023年4月21日星期五

第六讲：仪器的原理与使用

2

声明

本讲稿中引用的图、表、数据全部取自

公开发表的书籍、文献、论文，而且仅为教

学使用，任何人不得将其用于商业目的。

磁性测量仪器篇之一

MPMS 的介绍

4

主要内容

• 提拉样品磁强计的原理和型式步进提拉方式（ MPMS ）匀速提拉方式（ ESM 、 ACM

S ）往复提拉方式（ RSO ）• MPMS 的主要功能及其使用温度、磁场的控制磁矩的检测、功能样品、维护、注意事项

物理所磁学室公共测试讲座

共 135 页

5

提拉样品磁强计

Extracting Sample Magnetometer(ESM)

感谢 ?

6

ESM 的基本要求

• 样品永远在线圈内部• 样品平行于线圈轴向运动• 类似于平行于轴向的 VSM

• 无法在有极头的磁体系统中使用

7

ESM 的基础 -1 ESM1

抛移线圈：冲击法（课程六）

0 ,0 , , S Nt B H T t C

CS, N ：线圈磁通常数

迴线仪

0 0 00( , , ) ( , , )S S

r r rtB m d S B m d St

tt t

t t

��

8

ESM 的基础 -2 ESM2

点磁偶极子（ point dipole ）假设 ?

0 0( )r t x x i y kty j z

n

x

y

z

O

(x0, y0, z)

(x, y, 0)

检测线圈

m��

( )r t

rc

0

5 3

3( , , )

4

m r r mB m r t

r r

��

检测线圈内的磁通量：

( , , )S

t B m r t d S ��

检测线圈内的磁场强度：

5

9

与 VSM 相同的处理方法 ESM3

样品位于检测线圈的轴线上

2

20

0 32

, ,2

c

c

z rt

mz

zm

tr

单匝检测线圈内的磁通量：

单匝检测线圈内的感应电势：

0

0

20

5

2

22

, , 3( , , )

2c

c

zm mt r

tz z t z t

ztz tt r

m

平行于轴向的 VSM

10


样品偏离轴线距离单匝检测线圈内的磁通量： n ＝ 2

2

2 0 22

2

2

3 2,

2, , , , 1

4

cc c

c

rr rt t

r

z tz z

z t

zm

tm

单匝检测线圈内的感应电势： n ＝ 2

2 2

2

2

2 02 22

5, , , , , 1

4

3 4

c

cc r z tz z

z t

rtm m t

r


11


一级梯度线圈（串联反接的两个相同线圈）

, , , , , , ,i

i

SS

z zN mtm t

一级梯度线圈

+

_1

_ 2

, ,2

,

,2

,

, , ,

Coil

Coil

t t N

t N

z

m z

m


12


二级梯度线圈（串联的两组一级梯度线圈）

, , , , , , ,i

i

SS

z zN mtm t

_ _1&2

_

_

, , , ,

, , , ,

, , , ,

2 Coil center

Coil top

Coil bottom

t t Nm z

t

m

z Nm

tz N


二级梯度线圈 (MPMS)

+

13

磁通量与点磁偶极子位置单匝检测线圈：可以测量均匀磁场的变化

ESM?

14

磁通量与点磁偶极子位置一级梯度线圈：可以抵消均匀磁场

ACMSVSM 10

15

磁通量与点磁偶极子位置二级梯度线圈：可以抵消均匀的背景

MPMSSVSM

16

ESM 仪器设备 ESM6

ESM 的原理：积分式磁强计

t

ε

0 t0 2t0

+ －

dt

dt

)(

1. 提拉速率：高2. 使用积分器3. 磁矩定标： Ni

4. 灵敏度低于 VSM

5. 开路测量

1. 提拉速率：高2. 使用积分器3. 磁矩定标： Ni

4. 灵敏度低于 VSM

5. 开路测量

17


ESM 的构成

1. 均匀磁场：2. 样品提拉系统：3. 信号采集系统：4. 测量控制系统

SS

SdZtTHBSdZtTHB

),,,(),,,( 11112222

0( , , , ) ( , ) ( , , , )B H T t Z H t Z M H T t Z 其中，

0 ( )( , , , ) ( , ) ZB H T t Z H M H T

( ) 1Z ( ) 0Z

dtK

THM

THMKt

02

1),(

),(2

清零

18


ESM ：磁矩的检测

0( , , , ) ( , ) ( , , , )B H T t Z H t Z M H T t Z Z

0( , , , ) ( , )B H T t Z H M H T ( ) 1Z

( ) 0Z HZtTHB ),,,(

19

提拉样品磁强计 ESM9

ESM 的现状

1. 单点测量时间短、灵敏度略低；2. PPMS_ACMS 的直流磁性测量采用提拉法；3. MPMS 、 MPMS XL 的直流磁性测量；4. 磁学室原有一台 ESM （ CF-1 型）；5. 现在已经很少有独立的 ESM 。

1. 单点测量时间短、灵敏度略低；2. PPMS_ACMS 的直流磁性测量采用提拉法；3. MPMS 、 MPMS XL 的直流磁性测量；4. 磁学室原有一台 ESM （ CF-1 型）；5. 现在已经很少有独立的 ESM 。

15

20

几种 ESM 的介绍步进提拉方式（ MPMS ）

匀速提拉方式（ ESM 、 ACMS ）往复提拉方式（ MPMS_RSO ）

21

步进、匀速、往复

一级梯度线圈 (ESM)

+


+


+


+

22

MPMS 、 MPMS XL

基本工作原理各种功能的介绍使用中的注意事

项人身、财产安全样品几何、安装具体功能的限制

23

MPMS 的原理 MPMS1

QD_MPMS （ XL ）

By Mike McElfresh

Fundamentals of Magnetism and Magnetic Measurements

Featuring Quantum Design’s Magnetic Property Measurement System

http://www.qdusa.com/sitedocs/appNotes/mpms/FundPrimer.pdf

24

名词：超导量子磁强计中华人民共和国计量技术规范 JJG 1013 －89

《磁学计量常用名词术语及定义（试行）》

4.95 超导量子磁强计： Superconducting Quantum magnetometer

中华人民共和国计量技术规范 JJG 1013 －89

《磁学计量常用名词术语及定义（试行）》

4.95 超导量子磁强计： Superconducting Quantum magnetometer

中文：超导量子磁强计； SQUID 磁强计

英文： SQUID Magnetometer ； SQUID (Superconducting Quantum

Interference Device) Magnetometer20

25

量子设计公司及其产品

26

DOU 升级了超导室（ MPMS-5S ）、磁学室（ MPMS-

7 ）

25

10

15

27

课后作业－ 1

你知道 MPMS 具体细节的哪些内容？对于 MPMS XL 新功能有何评价？

The ChronologyThe Chronology

1911 – Heike Kammerlingh Onnes discovers superconductivity1911 – Heike Kammerlingh Onnes discovers superconductivity• 1913 Receives the Nobel Prize in Physics1913 Receives the Nobel Prize in Physics

1962 – Brian Josephson predicts the “Josephson Effect”1962 – Brian Josephson predicts the “Josephson Effect”• 1973 Receives the Nobel Prize in Physics1973 Receives the Nobel Prize in Physics

1986 – Bednorz and Muller discover High Temperature 1986 – Bednorz and Muller discover High Temperature SuperconductivitySuperconductivity• 1987 They receive the Nobel Prize in Physics1987 They receive the Nobel Prize in Physics

After Bill of QD, 2006

The SQUIDThe SQUID

Within a year of Brian Josephson’s discovery, the first Within a year of Brian Josephson’s discovery, the first Superconducting Quantum Interference Device (SQUID) was builtSuperconducting Quantum Interference Device (SQUID) was built

In 1968, Professor John Wheatley of In 1968, Professor John Wheatley of UCSDUCSD and four other and four other international physicists founded S. H. E. Corp. (Superconducting international physicists founded S. H. E. Corp. (Superconducting Helium Electronics) to commercialize this new technology.Helium Electronics) to commercialize this new technology.


25

SQUID MagnetometersSQUID Magnetometers The first SQUID magnetometer was developed by The first SQUID magnetometer was developed by Mike SimmondsMike Simmonds, ,

Ph.D. and Ph.D. and Ron SagerRon Sager, Ph.D. while at S.H.E. Corporation in 1976., Ph.D. while at S.H.E. Corporation in 1976. In 1982, Mike and Ron, along with two other SHE employees, founded In 1982, Mike and Ron, along with two other SHE employees, founded

Quantum Design.Quantum Design. In 1984, QD began to market the next generation SQUID magnetometer – the In 1984, QD began to market the next generation SQUID magnetometer – the

Magnetic Property Measurement System (MPMS).Magnetic Property Measurement System (MPMS). In 1996, QD introduced the MPMS XL as the latest generation SQUID In 1996, QD introduced the MPMS XL as the latest generation SQUID

magnetometermagnetometer During the past 22 years, six companies have unsuccessfully designed and During the past 22 years, six companies have unsuccessfully designed and

marketed SQUID magnetometers to compete with the MPMS. marketed SQUID magnetometers to compete with the MPMS. 26


MPMS XL Temperature ControlMPMS XL Temperature Control Patented dual impedance design allows continuous operation below Patented dual impedance design allows continuous operation below

4.2 K4.2 K Sample tube thermometry improves temperature accuracy and controlSample tube thermometry improves temperature accuracy and control Transition through 4.2 K requires no He reservoir refilling and Transition through 4.2 K requires no He reservoir refilling and

recycling (no pot fills)recycling (no pot fills) Temperature sweep mode allows measurements while sweeping Temperature sweep mode allows measurements while sweeping

temperature at user controlled ratetemperature at user controlled rate• Increases measurement speedIncreases measurement speed

Smooth temperature transitions through 4.2 K both cooling and Smooth temperature transitions through 4.2 K both cooling and warmingwarming


MPMS XL Temperature ControlMPMS XL Temperature Control


MPMS 、 SQUID_VSM ：独立的温度、气氛环境




我的评价

30


我的评价

Set Temperature 10 KWait for temperature stable 30 min

70 min


我的评价

OverShoot!

Stabilizing!

JIm (QD):

The idea is just to wait some extra time for upper section

(stainless steel slow to change) of sample tube to cool do

wn and get lower thermal gradient. Otherwise, the extra he

at load will prevent stabilizing and/or holding 2 K.

37

程序设定：

在 10 K 快速稳定的小技巧• 重复设定温度 10

K

手动：

Set Temperature 10 K

Set Temperature 10.000K at 10.000K/min.Waitfor Delay:1800secsSet Temperature 10.000K at 10.000K/min.Waitfor Delay:300secsSet Temperature 10.000K at 10.000K/min.Waitfor Delay:300secsSet Temperature 10.000K at 10.000K/min.Waitfor Delay:300secs

38

Wait for

• Wait for

• Wait for Temp Stable

• Wait for Temperature

• Wait for Field

• Wait for Position


Temperature Range: Temperature Range: 1.9 - 400 K (800 K with optional oven)1.9 - 400 K (800 K with optional oven) Operation Below 4.2 K: Operation Below 4.2 K: ContinuousContinuous Temperature Stability: Temperature Stability: ±0.5% ±0.5% Sweep Rate Range: Sweep Rate Range: 0.01 - 10 K/min with smooth transitions 0.01 - 10 K/min with smooth transitions

through 4.2 Kthrough 4.2 K Temperature Calibration Temperature Calibration ±0.5% typical ±0.5% typical

Accuracy: Accuracy: Number of Thermometers: Number of Thermometers: 2 (one at bottom of sample tube; one at 2 (one at bottom of sample tube; one at

the the location of sample measurements)location of sample measurements)


35

40

MPMS2两种控温模式

41

T1＋

－

时间

温度

控温模式：单点设定温度设定温度： T 1 KelvinSet Temperature to ： T 1 Kelvin

升温测量

显示QUENSQ

20 秒 40 秒

如果温度在 T1内系统认为温度稳定

显示温度

实际温度

MPMS3

Tolerence

＝ 0.005 T 1

42

时间

温度

2T1

控温模式：单点设定温度

降温测量？

显示温度

实际温度

MPMS4

？

43

控温模式：扫描温度

扫描温度到： T S Kelvin

Set Temperature to ： T 1 Kelvin

Sweep Rate ： 1 mK/min～ 10 K/min

Sweep Temperature to ： T S Kelvin

扫描到某一温度

设定起始温度

设定变温速率

扫描到某一温度

MPMS5

44

时间

温度

控温模式：扫描温度

同时进行升温、降温测量

T S

T F

T = (T S ＋ T F)/2

测量过程中温度变化测量

开始 /结束

测量结束 / 开始

MPMS6

Sweep Temperature 40

Very high homogeneity magnets (1, 5 and 7 Tesla)• 0.01% uniformity over 4 cm

Magnets can be operated in persistent or driven mode • Hysteresis mode allows faster hysteresis loop measurements

Magnets have two operating resolutions: standard and high resolution

Magnetic Field ControlMagnetic Field Control

Type of Magnet Standard resolution High resolution1 tesla 0.5 Oe 1.0 tesla 0.05 Oe 1500 Oe5 tesla 1 Oe 5.0 tesla 0.1 Oe 5000 Oe7 tesla 2 Oe 7.0 tesla 0.2 Oe 6000 Oe


Hysteresis MeasurementHysteresis Measurement


47

SQUID 磁强计磁场控制示意图MPMS7

可调电阻

电源

R

E

K

I

I2 I1

超导开关开关电阻 r

闭环： r = 0 ； I2 = -I1

开环： r = rn ； I2 = 0

超导磁体液氦

闭环运行开环运行不加热

电源开关

加热

48

SQUID 磁强计磁场升－降过程

磁场降磁场升

电源电流

开关状态

线圈电流

开关电流

MPMS8

49

磁场变化的模式开环模式： Hysteresis Mode

开关电阻为正常态；电源与超导磁体线圈保持接通；实际磁场与设定值相差一小量。

闭环模式： No Overshoot Mode

闭环模式： Oscillate Mode

H

MPMS9 － 1

45

50

开环运行时的磁场噪声开环模式： Hysteresis Mode

MPMS9 － 2

51

关于变场速率• 电感－电源电压

coilsource

souri

cl

eco

d

dt

di

tL

d

Lcoil ： 20 H ～ 35 H

source ： 2.0 V ～ 5.0 V

A/ssourc

coil

urce eso

L

di

dt

52

关于变场速率• 电感－电源电压

磁体线圈电感（ H ） 20 ～ 35

磁体电源电压（ V ） 2.0 ～ 5.0

电流变化最高速率（ A/s ） 0.057 ～ 0.25

磁场变化最高速率（ Oe/s ）

/ ( ) [T/A]B

B I atioI

r

磁场 /电流比：（线圈几何灵敏因子）

2062.71 Oe/A

117 Oe/s ～ 515 Oe/s

MPMS10

53

互易性原理 VSM7

均匀磁化（ homogeneous magnetization ）

rc

z(t)

coilg

dr td tt

dtm

dtr

I

m

coil

B rg r

I

coil

B rk r

I定义：

coil

k rg

k r k r

x yr

z

圆形电流线圈的磁场（春）

gcoil ：几何（位置）灵敏因子

小样品！

课程三

54

MPMS-7 型超导量子磁强计介绍

纵向探测系统： Longitudinal Moment Detection System

MPMS11

QUENSQ

50

55

SQUID 磁强计磁矩检测系统

Straw-like

MPMS12

样品架样品架为什么要调节样品的中心位置

Reciprocating Sample Measurement SystemReciprocating Sample Measurement System(RSO)(RSO)


Reciprocating Sample Measurement SystemReciprocating Sample Measurement System(RSO)(RSO)

Frequency Range:Frequency Range: 0.5 - 4 Hz0.5 - 4 Hz Oscillation Amplitude:Oscillation Amplitude: 0.5 - 50 mm0.5 - 50 mm Relative Sensitivity:Relative Sensitivity: 1 x 101 x 10-8-8 emu emu; H ; H 2,500 Oe, T = 100 2,500 Oe, T = 100

K K (for 7-tesla magnet)(for 7-tesla magnet)

6 x 106 x 10-7-7 emu; H @ 7 tesla, T = 100 K emu; H @ 7 tesla, T = 100 K (for (for 7-tesla magnet)7-tesla magnet)

Dynamic rangeDynamic range 1010-8-8 to 5 emu (300 emu with Extended to 5 emu (300 emu with Extended Dynamic Range option)Dynamic Range option)


58

MPMS RSO 的原理 MPMS RSO 1

原理上的可行性

2

20

0 32

, ,2

c

c

z rt

mz

zm

tr

0

0

20

5

2

22

, , 3( , , )

2c

c

zm mt r

tz z t z t

ztz tt r

m

单匝检测线圈内的磁通量：

单匝检测线圈内的感应电势：

59

磁通量与点磁偶极子位置二级梯度线圈：可以抵消均匀的背景

MPMSSVSM

RSO

55

60



20

0 32

2

32

2

2

2

2 32

2, ,

2c

c

c

c

c

c

z rt

r

r

r

r

r

zz t

z t

z

m

t

m

二级梯度线圈内的磁通量：

二级梯度线圈

+

61



max max

2max m

2 22 2 2 2max

7/ 2 7/ 2 7 / 22 2 22ax max

2

2 4 4 40

c c c

c c c

z r r rz z

z z zr r r

二级梯度线圈内的磁通量对位置的导数：

max ,cf rz

只与线圈的尺寸和相对位置有关，是确定的。

？

MPMS XL ： 0.62 cm （ QD ）、 0.587 cm （计算）

rc＝ 0.97 cm＝ 1.519 cm

62

MPMS RSO 的使用 MPMS RSO 4

1 、硬件：使用伺服马达驱动专用 RSO 传输台（ RSO motor ）

2 、功能：实现 MPMS 的快速测量磁矩～磁场、温度关系

3 、适用性：磁矩上限： 0.5 emu ？仅适用于所有的磁性测量

JIm:

Yes, EDR is automatically enabled with RSO, whenever over-

range error reported at normal maximum 1.25 emu scale.

63


硬件：专用 RSO 传输台（ RSO motor ）

64


样品取放： Air Lock

必须 100 K 以上温度取放样品！可以在任何温度取放样品！

60

65


4 、样品位置：中心、最大斜率？原则上，中心位置仍然是最佳选择－ Jim

弱磁性信号的样品对磁场均匀性敏感的材料

必须对称！必须地！

MPMS System OptionsMPMS System Options

Transverse Moment DetectionTransverse Moment Detection• for examining anisotropic effectsfor examining anisotropic effects

• Second SQUID detection systemSecond SQUID detection system SQUID AC SusceptibilitySQUID AC Susceptibility

• 2 x 102 x 10-8-8 emu sensitivity 0.1 Hz to 1 emu sensitivity 0.1 Hz to 1 kHzkHz

Ultra-Low FieldUltra-Low Field• Reduce remanent magnet field to Reduce remanent magnet field to ±±0.0.

05 Oe05 Oe Extended Dynamic RangeExtended Dynamic Range

• Measure moments to ±300 emuMeasure moments to ±300 emu External Device ControlExternal Device Control

• Control user instruments with the MControl user instruments with the MPMSPMS

10 kBar Pressure Cell10 kBar Pressure Cell

Sample RotatorsSample Rotators• Vertical and HorizontalVertical and Horizontal

Sample Space OvenSample Space Oven• Temperatures to 800 KTemperatures to 800 K

Environmental Magnetic ShieldsEnvironmental Magnetic Shields Fiber Optic Sample HolderFiber Optic Sample Holder

• Allows sample excitation with lightAllows sample excitation with light Manual Insertion Utility ProbeManual Insertion Utility Probe

• Perform elector-transport Perform elector-transport measurements in MPMSmeasurements in MPMS

Liquid Nitrogen Shielded DewarLiquid Nitrogen Shielded Dewar EverCool Cryocooled DewarEverCool Cryocooled Dewar

• No-Loss liquid helium dewarNo-Loss liquid helium dewar

• No helium transfersNo helium transfers


13+1

Transverse Moment DetectionTransverse Moment Detection

Measures anisotropic effects of Measures anisotropic effects of moments with vector moments with vector components perpendicular to components perpendicular to the applied fieldthe applied field

Incorporates a second SQUID Incorporates a second SQUID detection system which can detection system which can resolve transverse moments as resolve transverse moments as small as 10small as 10-6-6 emu emu

Second-order detection coils Second-order detection coils orthogonal to the longitudinal orthogonal to the longitudinal detection coilsdetection coils


SQUID AC SusceptibilitySQUID AC Susceptibility Dynamic measurement of sampleDynamic measurement of sample

• Looks also at the resistance and conductanceLooks also at the resistance and conductance

• Can be more sensitive the DC measurementCan be more sensitive the DC measurement Measures Real (Measures Real () and Imaginary () and Imaginary () components) components

is the resistance of the sampleis the resistance of the sample is the conductive partis the conductive part

Proportional to the energy dissipation in the sampleProportional to the energy dissipation in the sample

Must resolve components of sample moment that is out of phase with Must resolve components of sample moment that is out of phase with the applied AC fieldthe applied AC field• SQUID is the best for this because it offers a signal response that is SQUID is the best for this because it offers a signal response that is

virtually flat from 0.01 Hz to 1 kHzvirtually flat from 0.01 Hz to 1 kHz Available on all MPMS XL systemsAvailable on all MPMS XL systems Requires system to be returned to factory for upgradeRequires system to be returned to factory for upgrade


SQUID AC SusceptibilitySQUID AC Susceptibility FeaturesFeatures

• Programmable Waveform Synthesizer and high-speed Analog-to-Digital Programmable Waveform Synthesizer and high-speed Analog-to-Digital converterconverter

• AC susceptibility measured automatically and can be done in combination AC susceptibility measured automatically and can be done in combination with the DC measurementwith the DC measurement

• Determination of both real and imaginary components of the sample’s Determination of both real and imaginary components of the sample’s susceptibilitysusceptibility

• Frequency independent sensitivityFrequency independent sensitivity SpecificationsSpecifications

• Sensitivity (0.1 Hz to 1 kHz):Sensitivity (0.1 Hz to 1 kHz): 2 x 102 x 10-8-8 emu @ 0 Tesla emu @ 0 Tesla

1 x 101 x 10-7-7 emu @ 7 emu @ 7 TeslaTesla

• AC Frequency Range:AC Frequency Range: 0.01 Hz to 1 kHz0.01 Hz to 1 kHz• AC Field Range:AC Field Range: 0.0001 to 3 Oe (system dependent)0.0001 to 3 Oe (system dependent)• DC Applied Field:DC Applied Field: ±±0.1 to 70 kOe (system dependent)0.1 to 70 kOe (system dependent)


65

SQUID AC SusceptibilitySQUID AC Susceptibility


Ultra-Low Field CapabilityUltra-Low Field Capability

Actively cancels remanent field in all MPMS superconducting Actively cancels remanent field in all MPMS superconducting magnetsmagnets

Sample space fields as low as Sample space fields as low as ±±0.1 Oe achievable0.1 Oe achievable Custom-designed fluxgate magnetometer suppliedCustom-designed fluxgate magnetometer supplied Includes Magnet ResetIncludes Magnet Reset Requires the Environmental Magnet ShieldRequires the Environmental Magnet Shield


Hysteresis measurementHysteresis measurement


Extended Dynamic RangeExtended Dynamic Range

Extends the maximum measurable moment from ± 5 emu to ± 300 emu Extends the maximum measurable moment from ± 5 emu to ± 300 emu (10 orders of magnitude)(10 orders of magnitude)

Automatically selected when needed in measurementAutomatically selected when needed in measurement Effective on both longitudinal and transverse SQUID systems Effective on both longitudinal and transverse SQUID systems


74

关于 MPMS 的量程• 基本量程（ Primary Dynamic Range ）• 扩展量程（ Extended Dynamic Rang

e ）

70

75

关于 MPMS 的量程（ 1 ）• 基本量程（ Primary Dynamic Rang

e ）DC Transport ：

1.25 emu

4 cm, 32-point scan

10.0 emu

4 cm, 64-point scan

> 10.0 emu ？

Holding: 64 points per scan RSO ：0.4 emu

76

关于 MPMS 的量程（ 2 ）• 点数（提拉步数）与量

程DC Transport ：每步： 10 V

RSO ：

每步： 5 V

t

77

关于 MPMS 的量程（ 3 ）• 扩展量程（ Extended Dynamic Rang

e ）DC Transport ：RSO ：

300 emu

4 cm, 64-point scan

JIm ：EDR basically just puts a transformer between pick-up coil and SQUID capsule to reduce current generated in gradiometer by very large signals. While we of course calibrate the impact from extra electronic components, there will always be a distinct step in the data at this transition.

78

超导量子干涉器件的应用磁通的间接测量：电流负反馈

SQUID13

间接使用

x

Lp ， NpLs ， Ns

i ， LLead

M

L

p

p s leadfx fM

L LM

N

Li

ifrf

Output

SQUID检测电路

B ＝ 0

Mf

课程二

Sample Space OvenSample Space Oven Provides high temperature measurement capabilityProvides high temperature measurement capability

• Ambient to Ambient to 800 K800 K Easily installed and removed by the user when neededEasily installed and removed by the user when needed A minimal increase in helium usageA minimal increase in helium usage

• Approximately 0.1 liters liquid helium/hourApproximately 0.1 liters liquid helium/hour 3.5 mm diameter sample space3.5 mm diameter sample space

After Bill of QDAfter Bill of QD, 2006

75

MPMS Horizontal RotatorMPMS Horizontal Rotator

Automatically rotates sample about a horizontal axis during magnetic Automatically rotates sample about a horizontal axis during magnetic measurementmeasurement

360 degrees of rotation; 0.1 degree steps360 degrees of rotation; 0.1 degree steps Sample platform is 1.6 X 5.8 Sample platform is 1.6 X 5.8 Diamagnetic background signal of 10Diamagnetic background signal of 10-3-3 emu at 5 tesla emu at 5 tesla

（课程一）：样品总磁矩 < 0.1 memu


81

QD 公司 SQUID 磁强计的升级 Sample Rotator for MPMS?

82

水平旋转台• 打滑

Manual Insertion Utility ProbeManual Insertion Utility Probe

Perform electro-transport measurement in the MPMS sample spacePerform electro-transport measurement in the MPMS sample space 10-pin connector10-pin connector Use with External Device Control (EDC) for controlling external devices (e.g., Use with External Device Control (EDC) for controlling external devices (e.g.,

voltmeter and current source)voltmeter and current source)• Creates fully automated electro-transport measurement systemCreates fully automated electro-transport measurement system


http://www.http://www.qd-chinaqd-china.com/upfile/news/201071245437533.pdf.com/upfile/news/201071245437533.pdf

80

External Device ControlExternal Device Control

Allows control and data read back from third party electronicsAllows control and data read back from third party electronics Allows custom control of MPMS electronicsAllows custom control of MPMS electronics Use with Manual Insertion Utility Probe for automated electro-Use with Manual Insertion Utility Probe for automated electro-

transport measurementstransport measurements MPMS MultiVu version written in MPMS MultiVu version written in Borland’s DelphiBorland’s Delphi (Visual Pascal) (Visual Pascal)

programming languageprogramming language


Hysteresis MeasurementHysteresis Measurementmade with External Device Control (EDC)made with External Device Control (EDC)

Using EDCUsing EDC to control a DC field using the AC coil in the MPMS to control a DC field using the AC coil in the MPMS

Up to ± 8 Oe DC field (system dependent)Up to ± 8 Oe DC field (system dependent) Step size as small as 1.9 Step size as small as 1.9 OeOe

20 Å Ni Thin Film (PSI, Zurich)


Fiber Optic Sample HolderFiber Optic Sample Holder

Allows sample to be illuminated by an external light source while making Allows sample to be illuminated by an external light source while making magnetic measurementsmagnetic measurements

Optimized for near UV spectrum (180 to 700 nm)Optimized for near UV spectrum (180 to 700 nm) Includes 2-meter fiber optic bundleIncludes 2-meter fiber optic bundle Sample bucket 1.6 mm diameter and 1.6 mm deepSample bucket 1.6 mm diameter and 1.6 mm deep

Slide seal

Fiber optic bundle

SMA connector


Firberguide Industries: Superguide G UV-Vis fiber

http://www.http://www.qd-chinaqd-china.com/upfile/news/201071245437533.pdf.com/upfile/news/201071245437533.pdf

只与磁性测量兼容只与磁性测量兼容

MPMS Liquid Helium Dewar OptionsMPMS Liquid Helium Dewar Options

Basic system supplied with a vapor shielded 56 liter dewarBasic system supplied with a vapor shielded 56 liter dewar Liquid nitrogen jacketed version of the basic dewar improves hold Liquid nitrogen jacketed version of the basic dewar improves hold

time by ~ 30%time by ~ 30% MPMS EverCool Cryocooled DewarMPMS EverCool Cryocooled Dewar


85

MPMS EverCool DewarMPMS EverCool Dewar

Designed to eliminate the need for liquid helium transfersDesigned to eliminate the need for liquid helium transfers Virtually eliminates all helium loss from the Quantum Design MPMS Virtually eliminates all helium loss from the Quantum Design MPMS

magnetometer systemmagnetometer system Cryocooler-dewar system that recondenses the helium directly in the Cryocooler-dewar system that recondenses the helium directly in the

dewardewar Integrated into MPMS Operating SystemIntegrated into MPMS Operating System Cryocooler operation can be controlled automatically to minimize Cryocooler operation can be controlled automatically to minimize

interference with sensitive magnetic measurementsinterference with sensitive magnetic measurements Available as an upgrade to all MPMS systems (Available as an upgrade to all MPMS systems (nono equipment needs to equipment needs to

be returned to Quantum Design)be returned to Quantum Design) Available with water or air cooled compressorAvailable with water or air cooled compressor



CryocoolerCryocoolercoldheadcoldhead

Liquid heliumLiquid heliumcondenser unitcondenser unit


非常感谢物理所建立了低温条件保障中心！向在低温车间辛勤劳动的全体人员致敬！



New Product: New Product: High Pressure CellHigh Pressure Cell

Manufactured by easyLab Manufactured by easyLab Limited in the UKLimited in the UK

Offers 10 kbar of pressureOffers 10 kbar of pressure Supplied with complete Supplied with complete

user’s kituser’s kit

M06组


New Product: New Product: 33Helium SystemHelium System

Minimum temperature of 0.48KMinimum temperature of 0.48K Manufactured and marketed by Manufactured and marketed by

IQUANTUM of JapanIQUANTUM of Japan


90

95

超导量子磁强计的运行（条件）样品的安装（原则与方法）控制软件的启动和使用（方法）测量程序的编辑（过程）数据文件的处理（注意事项）

超导量子磁强计的操作

MPMS操作 1


认真阅读仪器的《使用手册》

严格按照操作程序操作

MPMS操作 2

我本人非常同情黄伟文同志…的…

安全

97

超导量子磁强计的运行（条件）

1 、使用液氦总容量： 56 升；初次冷却： 100 升；液氦的自然蒸发： 3 升～ 5 升 / 天（ 5 K 时） 30 % 以下：必须输入液氦； 50 % 以上： 5 T 磁

场

2 、电力要求交流（ 2205 % ） V

3 、环境要求温度（ < 30 C ）、湿度（ < 80 % ）

超导量子磁强计的操作MPMS操作 3

98

样品的安装（原则与方法）探测线圈的设计原理超导量子磁强计的磁矩探测线圈采用 Second-order Gradiometer

几何构形。最主要特点是：当一个均匀的长样品在探测线圈中移动时，只要样品的长度远远大于探测线圈的长度，则该样品在探测线圈中不会产生信号。

样品架的选择石英管、吸管厚度均匀、质量轻、密度低、磁化率小、热稳定性高

安装样品的方法（推荐）样品尺寸缩小、样品径向居中、内外压力平衡、样品刚性安放

超导量子磁强计的操作样品安装 1

99

95

100

超导量子磁强计的操作样品安装 2

• 磁性测量样品的安放原则

1 、样品尺寸尽量小2 、样品在磁场方向对称3 、样品在径向居中4 、刚性固定

9 mm6 mm

H

101

关于薄膜样品• 样品尺寸、方向

L

L

102

二级梯度线圈

+

关于薄膜样品• 样品尺寸、方向（竖直放置）

103

关于薄膜样品• 样品尺寸、方向（竖直放置）

104

二级梯度线圈

+

关于薄膜样品• 样品尺寸、方向（水平放置）

100

105

关于薄膜样品• 样品尺寸、方向（水平放置）

106

关于薄膜样品• 样品尺寸、方向（比较： 5点）

H

M

O

5 mm 5 mm

1.117

1.000

0.936

107

关于薄膜样品• 样品尺寸、方向（比较：均匀磁化）

L

L

108

关于弱磁性信号的样品• 背景、背景的扣除

自动扣除背景：能用！

信号：～ 100 背景：～ 10

100 10 10100% 0.909

100 10

信号：～ 1.05 背景：～ 1.00

1.05 1.00 1.00100% 0.51219

1.05 1.00

MPMS XL 、 VSM

信号：～ 0.10 背景：～ 1.00

0.10 1.00 1.00100% 0.0909

0.10 1.00

109

关于弱磁性信号的样品• 降低背景信号

足够长（ > 6 cm ）

关于胶带： Kapton

105

110

关于弱磁性信号的样品• 粉末

足够长（ > 6 cm ）

只测量内禀参数：

111

超导量子磁强计的操作• 样品的安放：磁性测量样品

B

C

D

A

径向定位平衡压力用微孔

样品安装 3

112

理想情况的响应曲线

如何判断样品的安装质量（ 1 ）1. 对称性；2. 多次调节中心的重复性

脱脂棉

样品

足够长（ > 6 cm ）

113


如何判断样品的安装质量（ 2 ）响应曲线：薄膜样品

L

L

114


如何判断样品的安装质量（ 3 ）响应曲线：圆柱体样品

D

H

2 3 4:12 , , ,

8 8 8 8

D D D DSampling

上下两个表面各取 48个点计算（均匀磁化）

D (mm) 1.0 2.0 3.0 4.0 5.0

L (mm) 0.048 0.096 0.144 0.197 0.236

110

115

样品的总磁矩样品5

样品架（非样品）的磁矩：

H

磁矩中心样品

吸管

胶囊

脱脂棉

对称性！

课程一

116


L L L

两端法：外加电流，测电压（电流与电压共线）四端法：外加电流，测电压（电流与电压不共线）两端法：外加电压，测电流（电流与电压共线） van de Pauw 法：霍耳效应测量：

• 样品的安放：电性（接触）测量样品

样品安装 4

117

关于电输运的测量• 根本问题－连线、接触点

异质材料之间的接触电势

热电势（温差电势）1

( , ) ( , )( )

high

cold

TB

A hot cold ATA

kE T T d N T

e N T

( )( , ) ln

( )

high

cold

TB A

AB hot cold TB

k N TE T T dT

e N T

( )( ) ln

( )B A

ABB

k T N TE T

e N T

物理存在

热电偶

118

关于电输运的测量• 常见问题－虚焊

清洁表面、助焊剂、超声压焊

• 注意事项－消除温差电势

Meter

同质材料

同质材料两引线应该使用相同材料；异质材料的连接点应该处于相同的温度；同质材料的两端的温度应该相同

电阻 < 0 ?电阻 < 0 ?

IoutIin

V+ V-

环境电噪声

119

课后作业－ 2

在测量电阻时，需要考虑哪些因素？不同的阻值范围，采用的测量方法有何不同？

115

120

超导量子磁强计的维护及注意事项•液氦、温度、磁场

液面计

100％

50％40％30％

60％

液氦

温度磁场

MPMS 维护 1

121

超导量子磁强计的维护及注意事项•液氦液面与最大可使用的磁场

100 ％

7.0 特斯拉90 ％80 ％70 ％60 ％

5.0 特斯拉50 ％

1.0 特斯拉40 ％

0.1 特斯拉30 ％

< 0.01 特斯拉20 ％

MPMS 维护 2

122

2 、样品室保持样品室清洁（准确度）

保证样品杆密封（下页）

超导量子磁强计的维护及注意事项

He

1 、控制用计算机严禁修改MPMSR2快捷方式的设置

软盘必须查 /杀病毒

MPMS 维护 3

123

超导量子磁强计的维护及注意事项• 保持样品腔的清洁（验证、检查）

MPMS 维护 4

1 、在样品杆上安装一支干净的空吸管；

2 、设定磁场 1.0 T （闭环）；

3 、测量 M ～ T 曲线（ 1.8 K ～ 300 K ）；

4 、验证。

T

M

～ 108 emu

124

超导量子磁强计的维护及注意事项• 保持样品杆密封良好（防止结冻、固态氮氧）

Grease seal

MPMS 维护 5

注意 O 圈

120

125

• 固态 O2 的反铁磁峰

样品室有大量空气凝结的结果

126

样品室密封• 经历固－液转变点

5.6 mmole

127

样品室连续抽气• 经历固－液转变点

5.6 mmole

128

举轻若重• 液氦的价格

2000 年：～ 50 元 / 升； 2007 年： 80元 / 升； 2009 年：～ 200元 / 升

• 氦的密度

400元 / 升

氦气 (273 K, 1 atm) ： 0.178 47 g/L ；液氦： 0.124 98 kg/L

氦气 (273 K, 1 atm) ： 5 603 L/kg ；液氦： 8.001 3 L/kg

1 kg液氦～ 8 L液氦； 1 L液氦～ 700 L氦气

• 人的肺活量：～ 3.5 L 1 块钱！

～ 15 呼吸 / 分钟

http://image.baidu.com/i?ct=503316480&z=&tn=baiduimagedetail&word=%C8%CB%CE%EF%BF%A8%CD%A8%CD%BC%C6%AC&in=11215&cl=2&lm=-1&pn=11&rn=1&di=28933166790&ln=2000&fr=ala0&fmq=&ic=&s=&se=&sme=0&tab=&width=&height=&face=

129

MPMS XL 的新功能• Multiple Measure

125

130

MPMS XL 的新功能• Multiple Measure (Sequence Command)

131

MPMS XL 的新功能• Multiple

Measure

132

MPMS XL 的新功能• Multiple Measure命令的使

用

133

MPMS XL 的新功能• Multiple Measure命令的使

用

134


Measure

n

m

k

130

135

剔除异常值的方法• 国家标准

GB/T 4883-1985

《数据的统计处理和解释正态样本异常值的判断和处理》GB/T 8056-1987

《数据的统计处理和解释指数样本异常值的判断和处理》

检出异常值的个数不超过 1 ：Grubbs 检验法、 Dixon 检验法

检出异常值的个数上限大于 1：

偏度－峰度检验法、 Dixon 检验法

观测值个数 3

MPMS XL ：Multiple Measure

136

实验标准偏差Bessel 公

式n次测量结果： x1, x2, …, xi, …, xn

1

1 n

ii

xn

x

算术平均值：

2

1

1

1

n

iin

s x xx

实验（样本）标准偏差：

2

1

2

1

2

1

2

11

1

1

1

n

ii

n

ii

n

ii

s x s x x

s x s x

xn

nxn

x

n

的等价表达式1：

的等价表达式2：

单次测量的分散性

137

实验标准偏差Bessel 公

式n＝ 2 ： x1, x2

1 2

2x

x x算术平均值：

1 2

1

2i ix x x x x 单次测量的偏差：

1 2

1

2x x xs 实验标准偏差：

1

2ix s x 判据：

或者都保留或者都剔除

138

为什么• 两个数据点 x1＝ 1.456 9 、 x2＝ 2.038 7

1 2 1.747 82

xx x

算术平均值：

1 2 1 2

10.290 9

2x x x x 单次测量的偏差：

1 2

1 0.581 80.411 4

2 2x xs x 实验标准偏差：

i kx s x 判据： 2

2k

139


Measure

n>2

mn

ks(x)

135

Documents

中国科学院物理研究所 通用 实验技术公共课程

中国科学院物理研究所通用实验技术公共课程