Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio...

69
Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan

Transcript of Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio...

Page 1: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Some experimental approaches to study the aging phenomena in

spin glasses

Some experimental approaches to study the aging phenomena in

spin glasses

Tetsuya Sato Keio University  Yokohama, Japan

Tetsuya Sato Keio University  Yokohama, Japan

Page 2: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

OutlineOutline

Aging behavior of spin glass under bond perturbationAging behavior of spin glass under bond perturbation

· What is bond perturbation· Experimental procedure· Experimental result

· What is bond perturbation· Experimental procedure· Experimental result

Behavior of spin glass nanoparticle in magnetic fieldBehavior of spin glass nanoparticle in magnetic field

· Why is spin glass nanoparticle necessary· Experimental procedure· Experimental result

· Why is spin glass nanoparticle necessary· Experimental procedure· Experimental result

Concluding remarksConcluding remarks

Page 3: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

OutlineOutline

Aging behavior of spin glass under bond perturbationAging behavior of spin glass under bond perturbation

· What is bond perturbation· Experimental procedure· Experimental result

· What is bond perturbation· Experimental procedure· Experimental result

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

· Why is spin glass nanoparticle necessary· Experimental procedure· Behavior of spin glass nanoparticle magnetic field

· Why is spin glass nanoparticle necessary· Experimental procedure· Behavior of spin glass nanoparticle magnetic field

concluding remarksconcluding remarks

Page 4: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Aging behavior of spin glass under bond perturbation

1. What is bond perturbation

Aging behavior of spin glass under bond perturbation

1. What is bond perturbation

t w

tt = 0

TTHm

.

90

80

70

60

50

100 101 102 103 104

time (sec)

NiMn60.0 K

tw = 100 sec

tw = 1000 sec

tw = 10000 sec

.

8

6

4

2

0100 101 102 103 104

time (sec)

tw = 100 sec

tw = 1000 sec

tw = 10000 secNiMn60.0 K

· Wait time dependence· Wait time dependence

L(τ) = L0[k

BT ln(τ/τ

0)/Δ(T)]

1/Ψ

average size of excited droplet average size of excited droplet

Page 5: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Temperature perturbation Temperature perturbations, e.g., temperature cycle has been extensively used to study slow dynamics of spin glasses.

· Temperature perturbation Temperature perturbations, e.g., temperature cycle has been extensively used to study slow dynamics of spin glasses.

t

3000 s

ΔTTm

1000 s

TH10 s

t=00.35

0.30

0.25

0.20

0.15

0.10

0.05

0.0010

010

110

210

310

4

t (sec)

ΔT =0

ΔT =+ 2 KΔT =+ 4 K

ΔT =+ 8 K

NiMn

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0.0010

010

110

210

310

4

ΔT =0

ΔT =- 2 K

ΔT =- 4 K

ΔT =- 8 K

NiMn

t (sec)

tt = 0

ΔTTm

1000 sTH10 s

10 s

Temperature chaos Temperature chaos

Page 6: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Temperature perturbation · Temperature perturbation

1. temperature perturbation change in thermal excitation of droplet separation of time scale

1. temperature perturbation change in thermal excitation of droplet separation of time scale

tp(T

m+ΔT) = τ

0 [t

eff(T

m)/τ

0 ]

Tm

/(Tm

+ΔT)

ex)

When Tm

= 7 K, ΔT = 1K, τ0 = 10-13 s

8 K : 75 s 7 K : 10000 s

difference of 1K more than 100 times difference of time scale

2. temperature perturbation indirect change in bond interaction2. temperature perturbation indirect change in bond interaction

Page 7: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Bond perturbation · Bond perturbation

bond perturbation bond perturbation

Aging behavior of spin glass can be studied without separation of time scale.Aging behavior of spin glass can be studied without separation of time scale.

magnetic ionmagnetic ion

Page 8: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Bond perturbation · Bond perturbation

bond perturbation bond perturbation

magnetic ionmagnetic ion

Aging behavior of spin glass can be studied without separation of time scale.Aging behavior of spin glass can be studied without separation of time scale.

Page 9: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Bond perturbation · Bond perturbation

bond perturbation bond perturbation

magnetic ionmagnetic ion

· method for bond perturbation · method for bond perturbation

carrier excitation in semicondcutor change in interactioncarrier excitation in semicondcutor change in interaction

photo illuminationphoto illumination

Page 10: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

2. Experimental procedure2. Experimental procedure

A. Bond and temperature perturbationsA. Bond and temperature perturbations

Sample

SQUID system

Optical fiber

ND filter

He-Ne laser

(543.5 nm, hν = 2.27 eV)

Optical fiber

straw

Cd0.63Mn0.37 (Te Eg = 2.18 eV)

1 mm

φ 3 mm

ΔT+ΔJ ΔT

Carbon coat

Sample

(ΔT perturbation + ΔJ perturbation) - (ΔT perturbation)(ΔT perturbation + ΔJ perturbation) - (ΔT perturbation)

= ΔJ perturbation = ΔJ perturbation

Page 11: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

2. Experimental procedure2. Experimental procedure

B. Bond perturbationB. Bond perturbation

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

Δ T

[ ]K

15001000500

[ ]time sec

sample temperature

lumination

SQUID

semiconductor lasersemiconductor laser

polarizerpolarizerPC control polarizer PC control polarizer

optical fiberoptical fiber

Photo intensity is changed synchronously with temperature controller so as to decrease change in sample temperature.

Photo intensity is changed synchronously with temperature controller so as to decrease change in sample temperature.

Deviation of temperature < 0.02 KDeviation of temperature < 0.02 K

Page 12: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

2. Experimental procedure2. Experimental procedure

H

t

Tm

tw tp

0

ΔT=0

ts

LIGHTT

H

t

Tm

tw

tp

0

ΔTts

LIGHTT

1. bond and temperature perturbations1. bond and temperature perturbations

2. bond perturbation2. bond perturbation

660

640

620

600

5801210864

T [K]

Tg = 10.7 K

ZFC

FC

6

5

4

3

2

1

010008006004002000

H [Oe]

Sample temperatureSample temperature

Field cooled magnetization Field cooled magnetization

Page 13: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

3. Experimental result3. Experimental result

1.0

0.8

0.6

0.4

0.2

no illuminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(a) ΔT=0.26KΔT

noilluminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(b) ΔT=0.26KΔT+ΔJ

1.0

0.8

0.6

0.4

0.2

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(c) ΔT=1.05KΔT

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(d) ΔT=1.05KΔT+ΔJ

tp(T

m+ΔT) = τ

0 [t

eff(T

m)/τ

0 ]

T/(T+ΔT)

A. bond and temperature perturbationsA. bond and temperature perturbations

Page 14: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1.0

0.8

0.6

0.4

0.2

no illuminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(a) ΔT=0.26KΔT

noilluminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(b) ΔT=0.26KΔT+ΔJ

1.0

0.8

0.6

0.4

0.2

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(c) ΔT=1.05KΔT

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(d) ΔT=1.05KΔT+ΔJ

tpeak

tp(T

m+ΔT) = τ

0 [t

eff(T

m)/τ

0 ]

T/(T+ΔT)3. Experimental result3. Experimental resultA. bond and temperature perturbationA. bond and temperature perturbation

Page 15: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

tp(T

m+ΔT) = τ

0 [t

eff(T

m)/τ

0 ]

T/(T+ΔT)

1.0

0.8

0.6

0.4

0.2

no illuminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(a) ΔT=0.26KΔT

noilluminationteff=125sec teff=380secteff=1100sec teff=1900secteff=3800sec teff=13000sec

(b) ΔT=0.26KΔT+ΔJ

1.0

0.8

0.6

0.4

0.2

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(c) ΔT=1.05KΔT

102 103 104t [sec]

noilluminationteff=230sec teff=720secteff=2200sec teff=3700secteff=7600sec teff=26000sec

(d) ΔT=1.05KΔT+ΔJ

sub peak

tpeak

sub peak

3. Experimental result3. Experimental resultA. bond and temperature perturbationA. bond and temperature perturbation

Page 16: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak

103

104

teff + tw [sec]

ΔTΔT+ ΔJ

(d) ΔT =1.05K

ΔTΔT+ΔJ

(b) ΔT =0.40K

103

104

ΔTΔT+ΔJ

(a) ΔT =0.26K

103

104

103 104

teff+ tw [sec]

ΔTΔT+ΔJ

(c) ΔT =0.69K

Page 17: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak

103

104

teff + tw [sec]

ΔTΔT+ ΔJ

(d) ΔT =1.05K

ΔTΔT+ΔJ

(b) ΔT =0.40K

103

104

ΔTΔT+ΔJ

(a) ΔT =0.26K

103

104

103 104

teff+ tw [sec]

ΔTΔT+ΔJ

(c) ΔT =0.69K

isothermal aging : tpeak

= teff

+ tw

isothermal aging : tpeak

= teff

+ tw

Page 18: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak

103

104

teff + tw [sec]

ΔTΔT+ ΔJ

(d) ΔT =1.05K

ΔTΔT+ΔJ

(b) ΔT =0.40K

103

104

ΔTΔT+ΔJ

(a) ΔT =0.26K

103

104

103 104

teff+ tw [sec]

ΔTΔT+ΔJ

(c) ΔT =0.69K

isothermal aging : tpeak

= teff

+ tw

isothermal aging : tpeak

= teff

+ tw

6

8100

2

4

103

104

teff [sec]

sub peaksub peak

Page 19: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

1.0

0.9

0.8

0.7

0.6

102

103

104

teff

[sec]

ΔT=0.26K

ΔT=0.40K

Filled:Open: ΔT+ΔJ

102 103 104

teff [sec]

ΔT=0.69K

ΔT=1.05K

Filled: ΔTOpen: ΔT+ΔJ

Page 20: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

1.0

0.9

0.8

0.7

0.6

102

103

104

teff

[sec]

ΔT=0.26K

ΔT=0.40K

Filled:Open: ΔT+ΔJ

102 103 104

teff [sec]

ΔT=0.69K

ΔT=1.05K

Filled: ΔTOpen: ΔT+ΔJ

r is intrinsically equal to 1.r is intrinsically equal to 1.

r deviates from 1.r deviates from 1.

Page 21: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

1.0

0.9

0.8

0.7

0.6

102

103

104

teff

[sec]

ΔT=0.26K

ΔT=0.40K

Filled:Open: ΔT+ΔJ

102 103 104

teff [sec]

ΔT=0.69K

ΔT=1.05K

Filled: ΔTOpen: ΔT+ΔJ

Difference between ΔT and ΔT+ΔJ perturbation disappears.Difference between ΔT and ΔT+ΔJ perturbation disappears.

r is intrinsically equal to 1.r is intrinsically equal to 1.

r deviates from 1.r deviates from 1.

Page 22: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

1.0

0.9

0.8

0.7

0.6

102

103

104

teff

[sec]

ΔT=0.26K

ΔT=0.40K

Filled:Open: ΔT+ΔJ

102 103 104

teff [sec]

ΔT=0.69K

ΔT=1.05K

Filled: ΔTOpen: ΔT+ΔJ

0.6

0.5

0.4

103

104

sub peaksub peakr is intrinsically equal to 1.r is intrinsically equal to 1.

r deviates from 1.r deviates from 1.

Difference between ΔT and ΔT+ΔJ perturbation disappears.Difference between ΔT and ΔT+ΔJ perturbation disappears.

Page 23: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Classification of aging behavior· Classification of aging behavior

P.E.Jönsson. R. Mathieu, P. Nordblad, H. Yoshino, H. Aruga Katori and A. Ito:Phys. Rev. B 70, 174402(2004).P.E.Jönsson. R. Mathieu, P. Nordblad, H. Yoshino, H. Aruga Katori and A. Ito:Phys. Rev. B 70, 174402(2004).

· Overlap length : L

ΔX = L

0|ΔX/J|

-1/ζ· Overlap length

: L

ΔX = L

0|ΔX/J|

-1/ζ

Non-perturbed state and ΔX-perturbed state are completely different on

large scale much beyond LΔX

.

Non-perturbed state and ΔX-perturbed state are completely different on

large scale much beyond LΔX

.

· Domain size after wait time tw : L

i(t

w) (initial stage)· Domain size after wait time t

w : L

i(t

w) (initial stage)

· Domain size under ΔX-perturbation after time tp :

Lp(t

eff) (perturbation stage)

· Domain size under ΔX-perturbation after time tp :

Lp(t

eff) (perturbation stage)

· Domain size without perturbation after time t : Lh(t)

(healing stage)

· Domain size without perturbation after time t : Lh(t)

(healing stage)

Page 24: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Classification of aging behavior· Classification of aging behavior

· Lp(t

eff) << L

ΔX Weakly perturbed regime

· L

p(t

eff) << L

ΔX Weakly perturbed regime

Accumulative aging       tpeak

= teff

+ tw

Recovery of order parameter in healing stage

Accumulative aging       tpeak

= teff

+ tw

Recovery of order parameter in healing stage

· Li(t

w), L

p(t

eff), L

h(t) >> L

ΔX Strongly perturbed regime

· L

i(t

w), L

p(t

eff), L

h(t) >> L

ΔX Strongly perturbed regime

Chaotic behavior        t

peak < t

eff + t

wDecrease in order parameter in healing stage

Appearance of sub peak

Chaotic behavior        tpeak

< teff

+ tw

Decrease in order parameter in healing stage

Appearance of sub peak

· Li(t

w), L

p(t

eff), L

h(t) ~ L

ΔX Crossover regime

· L

i(t

w), L

p(t

eff), L

h(t) ~ L

ΔX Crossover regime

Intermediate behavior between weakly and strongly perturbed regimesIntermediate behavior between weakly and strongly perturbed regimes

r ~ 1r ~ 1

r < 1r < 1

Page 25: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Classification of aging behavior· Classification of aging behavior

1.2

1.0

0.8

0.6

0.4

0.2

0.0

102

103

104

teff

[sec]

ΔT+ΔJ

W

WC

SCS

W

WC

SCS

1.2

1.0

0.8

0.6

0.4

0.2

0.0

ΔT

S : Strongly perturbed regime

SC : Crossover regime near strongly perturbed regime

WC : Crossover regime near weakly perturbed regime

W : Weakly perturbed regime

S : Strongly perturbed regime

SC : Crossover regime near strongly perturbed regime

WC : Crossover regime near weakly perturbed regime

W : Weakly perturbed regime

Page 26: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1.2

1.0

0.8

0.6

0.4

0.2

0.0

102

103

104

teff

[sec]

ΔT+ΔJ

W

WC

SCS

W

WC

SCS

1.2

1.0

0.8

0.6

0.4

0.2

0.0

ΔT

S : Strongly perturbed regime

SC : Crossover regime near strongly perturbed regime

WC : Crossover regime near weakly perturbed regime

W : Weakly perturbed regime

S : Strongly perturbed regime

SC : Crossover regime near strongly perturbed regime

WC : Crossover regime near weakly perturbed regime

W : Weakly perturbed regime

Shift of boundary curve Shift of boundary curve

· Classification of aging behavior· Classification of aging behavior

Page 27: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· Contribution of ΔJ· Contribution of ΔJ

Shift of boundary curveShift of boundary curve

decrease in overlap lengthdecrease in overlap length

LΔT+ΔJ

< LΔT

LΔT+ΔJ

< LΔT

1.0

0.9

0.8

0.7

0.6

102

103

104

teff

[sec]

ΔT=0.26K

ΔT=0.40K

ΔT+ΔJ

ΔT+ΔJ data with ΔT= 0.26 K

~ ΔT data with ΔT= 0.40 K

ΔT+ΔJ data with ΔT= 0.26 K

~ ΔT data with ΔT= 0.40 K

contribution of ΔJ perturbation with ΔT= 0.26 K

~ 014 K

contribution of ΔJ perturbation with ΔT= 0.26 K

~ 014 K

Page 28: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

B. Bond perturbationB. Bond perturbation

· check of ΔJ perturbation · check of ΔJ perturbation

1. Illumination on carbon side surface 1. Illumination on carbon side surface

6

4

2

010

210

310t [sec]

p=1500sec

p=3000sec

p=3000sectp=4500sec

tw tp= 6000sec

= 6% (ΔT=0.25K)(ΔT=0.49K)

(tw=6000sec)

ttt

+

noillumination

4

Open: I/I0Solid: I/I0 =12%

Page 29: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· check of ΔJ perturbation · check of ΔJ perturbation

1. Illumination on carbon side surface 1. Illumination on carbon side surface

6

4

2

010

210

310t [sec]

p=1500sec

p=3000sec

p=3000sectp=4500sec

tw tp= 6000sec

= 6% (ΔT=0.25K)(ΔT=0.49K)

(tw=6000sec)

ttt

+

noillumination

4

Open: I/I0Solid: I/I0 =12%

Independent of strength and duration of perturbationIndependent of strength and duration of perturbation

B. Bond perturbationB. Bond perturbation

Page 30: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· check of ΔJ perturbation · check of ΔJ perturbation

2. Photon energy hν smaller than energy gap Eg 2. Photon energy hν smaller than energy gap E

g

hν 149 eV

Eg = 2.18 eV

hν 149 eV

Eg = 2.18 eV

>>

5

4

3

2

1

0

102

103

10

[sec]

= 3000sec

t

tw = 3000sec

tp= 3000sec

4

no illumination

I / I0 = 0.246tw + tp

B. Bond perturbationB. Bond perturbation

Page 31: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· check of ΔJ perturbation · check of ΔJ perturbation

5

4

3

2

1

0

102

103

10

[sec]

= 3000sec

t

tw = 3000sec

tp= 3000sec

4

no illumination

I / I0 = 0.246tw + tp

hν 149 eV

Eg = 2.18 eV

hν 149 eV

Eg = 2.18 eV

>>

Intrinsically identicalIntrinsically identical

There is no contribution from photo illumination with low photon energy.There is no contribution from photo illumination with low photon energy.

B. Bond perturbationB. Bond perturbation

2. Photon energy hν smaller than energy gap Eg 2. Photon energy hν smaller than energy gap E

g

Page 32: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

B. bond perturbationB. bond perturbation

Page 33: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

no illumination tw

= 6000 secno illumination tw

= 6000 sec

B. bond perturbationB. bond perturbation

Page 34: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

chaoticchaotic

accumulativeaccumulative

B. bond perturbationB. bond perturbation

Page 35: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak

B. bond perturbationB. bond perturbation

Page 36: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak accumulative aging

: tpeak

= tp + t

w

accumulative aging

: tpeak

= tp + t

w

B. bond perturbationB. bond perturbation

Page 37: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· tpeak

· tpeak

chaoticchaotic

accumulativeaccumulative

B. bond perturbationB. bond perturbation

Page 38: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

B. bond perturbationB. bond perturbation

Page 39: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

slow decrease(chaotic)slow decrease(chaotic)

decrease independent of strength of perturbation decrease independent of strength of perturbation

Two-step changes in bond interaction ?Two-step changes in bond interaction ?

B. bond perturbationB. bond perturbation

Page 40: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

· relative peak hight r· relative peak hight r

ΔT = 0.40K temperature cycle ΔT = 0.40K temperature cycle

Difference between ΔJ and ΔT perturbations ?Difference between ΔJ and ΔT perturbations ?

B. bond perturbationB. bond perturbation

Page 41: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

4. Summary of aging behavior of spin glass under bond perturbation4. Summary of aging behavior of spin glass under bond perturbation

1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor. 1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor.

2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.

3. Plausible features of decrease in overlap length with ΔJ perturbation.3. Plausible features of decrease in overlap length with ΔJ perturbation.

4. Difference between ΔJ and ΔT perturbations in detail.4. Difference between ΔJ and ΔT perturbations in detail.

Page 42: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor. 1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor.

2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.

3. Plausible features of decrease in overlap length with ΔJ perturbation.3. Plausible features of decrease in overlap length with ΔJ perturbation.

4. Difference between ΔJ and ΔT perturbations in detail.4. Difference between ΔJ and ΔT perturbations in detail.

4. Summary of aging behavior of spin glass under bond perturbation4. Summary of aging behavior of spin glass under bond perturbation

Page 43: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor. 1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor.

2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.

3. Plausible features of decrease in overlap length with ΔJ perturbation.3. Plausible features of decrease in overlap length with ΔJ perturbation.

4. Difference between ΔJ and ΔT perturbations in detail.4. Difference between ΔJ and ΔT perturbations in detail.

4. Summary of aging behavior of spin glass under bond perturbation4. Summary of aging behavior of spin glass under bond perturbation

Page 44: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor. 1. Effective ΔJ perturbation by photo excitation in spin glass semiconductor.

2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.2. Observation of rejuvenation (chaotic) effect by ΔJ perturbation.

3. Plausible features of decrease in overlap length with ΔJ perturbation.3. Plausible features of decrease in overlap length with ΔJ perturbation.

4. Difference between ΔJ and ΔT perturbations in detail.4. Difference between ΔJ and ΔT perturbations in detail.

4. Summary of aging behavior of spin glass under bond perturbation4. Summary of aging behavior of spin glass under bond perturbation

Page 45: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

OutlineOutline

Aging behavior of spin glass under bond perturbationAging behavior of spin glass under bond perturbation

· What is bond perturbation· Experimental procedure· Experimental result

· What is bond perturbation· Experimental procedure· Experimental result

Behavior of spin glass nanoparticle in magnetic fieldBehavior of spin glass nanoparticle in magnetic field

· Why is spin glass nanoparticle necessary· Experimental procedure· Behavior of spin glass nanoparticle magnetic field

· Why is spin glass nanoparticle necessary· Experimental procedure· Behavior of spin glass nanoparticle magnetic field

Concluding remarksConcluding remarks

Page 46: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

Quantitative evaluation of spatial length scales and critical exponents, e.g.,Quantitative evaluation of spatial length scales and critical exponents, e.g.,

Page 47: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

Quantitative evaluation of spatial length scales and critical exponents, e.g.,Quantitative evaluation of spatial length scales and critical exponents, e.g.,

SG domain sizeCritical exponent ΨField crossover lengthCritical exponent δ ···

SG domain sizeCritical exponent ΨField crossover lengthCritical exponent δ ···

Page 48: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

· SG domain size· SG domain size

NanoparticlesNanoparticles

DD

Domain growth is restricted to the particle size D.Domain growth is restricted to the particle size D.

BulkBulk

L → ∞L → ∞

t → ∞t → ∞

Large droplet cannot reach the equilibrium state in experimental time scale.Large droplet cannot reach the equilibrium state in experimental time scale.

L = DL = D

Page 49: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

· SG domain size· SG domain size

NanoparticlesNanoparticles

DD

Domain growth is restricted to the particle size D.Domain growth is restricted to the particle size D.

BulkBulk

L → ∞L → ∞

t → ∞t → ∞

Large droplet cannot reach the equilibrium state in experimental time scale.Large droplet cannot reach the equilibrium state in experimental time scale.

L = DL = D

D ~ L(τ) ~ L0[k

BT ln(τ/τ

0)/Δ(T)]

1/Ψ D ~ L(τ) ~ L

0[k

BT ln(τ/τ

0)/Δ(T)]

1/Ψ

Droplet picture Droplet picture

Evaluation of SG domain size and Ψ Evaluation of SG domain size and Ψ

Page 50: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

Qualitative evaluation of spatial length scales and critical exponents, e.g.,Qualitative evaluation of spatial length scales and critical exponents, e.g.,

SG domain sizeCritical exponent ΨField crossover lengthCritical exponent δ ···

SG domain sizeCritical exponent ΨField crossover lengthCritical exponent δ ···

Page 51: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

Lh

Lh

· Field crossover length· Field crossover length

DD

Lh

> DLh

> D

Lh

Lh

DD

Lh

< DLh

< D

Page 52: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Behavior of spin glass nanoparticle magnetic fieldBehavior of spin glass nanoparticle magnetic field

1. Why is spin glass nanoparticle necessary1. Why is spin glass nanoparticle necessary

Lh

Lh

· Field crossover length· Field crossover length

DD

Lh

> DLh

> D

Lh

Lh

DD

Lh

< DLh

< D

Observation of crossoverObservation of crossover

Evaluation of field crossover length and δEvaluation of field crossover length and δ

D ~ Lh ~ l

Th

-δ D ~ L

h ~ l

Th

Droplet picture Droplet picture

Page 53: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

2. Experimental procedure2. Experimental procedure

• Reversed micelle method• Reversed micelle method

Ag(11 at.% Mn) nanoparticleAg(11 at.% Mn) nanoparticle

Ag+

Mn2+

H2O

NaBH4

H2O

Oactane

TEM imageTEM image

Anneal in vacuum with excessive addition of surfactants

Sample 1 : 400 °C for 6 hours

Sample 2 : 400 °C for 6 hours

Sample 3 : 450 °C for 6 hours

Page 54: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Sample 1

Sample 2

Sample 3

D ~ 44 nm

D ~ 51 nm

D ~ 53 nm

2. Experimental procedure2. Experimental procedure

Page 55: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

χ (10

-6

)emu

2824201612840 ( )Temperature K

= 5 H Oe = 10 H Oe = 50 H Oe = 100 H Oe = 200 H Oe = 300 H Oe = 400 H Oe = 500 H Oe = 1000 H Oe

1.4

1.2

1.0

0.8

0.6

0.4

0.2

χ (10

-6

/ )eum Oe

2824201612840

( )Temperature K

= 5 H Oe = 10 H Oe = 20 H Oe = 25 H Oe = 30 H Oe = 100 H Oe = 500 H Oe

5.0

4.0

3.0

2.0

1.0

0.0

χ (10

-6 )emu

2824201612840 ( )Temperature K

= 5 H Oe = 10 H Oe = 50 H Oe = 100 H Oe = 200 H Oe = 300 H Oe = 500 H Oe = 1000 H Oe = 5000 H Oe

Sample 1 Sample 2 Sample 3

3. Experimental result3. Experimental result

Page 56: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

χ (10

-6

)emu

2824201612840 ( )Temperature K

= 5 H Oe = 10 H Oe = 50 H Oe = 100 H Oe = 200 H Oe = 300 H Oe = 400 H Oe = 500 H Oe = 1000 H Oe

1.4

1.2

1.0

0.8

0.6

0.4

0.2

χ (10

-6

/ )eum Oe

2824201612840

( )Temperature K

= 5 H Oe = 10 H Oe = 20 H Oe = 25 H Oe = 30 H Oe = 100 H Oe = 500 H Oe

5.0

4.0

3.0

2.0

1.0

0.0

χ (10

-6 )emu

2824201612840 ( )Temperature K

= 5 H Oe = 10 H Oe = 50 H Oe = 100 H Oe = 200 H Oe = 300 H Oe = 500 H Oe = 1000 H Oe = 5000 H Oe

Sample 1 Sample 2 Sample 3

Field dependence of peak temperature Tpeak

.Field dependence of peak temperature Tpeak

.

3. Experimental result3. Experimental result

Page 57: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between L and TpeakRelation between L and Tpeak

3. Experimental result3. Experimental result

60

50

40

30

20

10

0

L (nm)

0.500.400.300.200.100.00

Tpeak /Tg

Page 58: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between L and TpeakRelation between L and Tpeak

3. Experimental result3. Experimental result

60

50

40

30

20

10

0

L (nm)

0.500.400.300.200.100.00

Tpeak /Tg

D ~ L(τ) ~ L0[k

BT

peak ln(τ/τ

0)/Δ(T)]

1/Ψ D ~ L(τ) ~ L

0[k

BT

peak ln(τ/τ

0)/Δ(T)]

1/Ψ

Page 59: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between L and TpeakRelation between L and Tpeak

3. Experimental result3. Experimental result

60

50

40

30

20

10

0

L (nm)

0.500.400.300.200.100.00

Tpeak /Tg

D ~ L(τ) ~ L0[k

BT

peak ln(τ/τ

0)/Δ(T)]

1/Ψ D ~ L(τ) ~ L

0[k

BT

peak ln(τ/τ

0)/Δ(T)]

1/Ψ

Ψ ~ 2.2 Ψ ~ 2.2

Θ Ψ < d-1 = 2Θ Ψ < d-1 = 2a little largea little large

Page 60: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between H and TpeakRelation between H and Tpeak

1000

750

500

250

0

Field (

Oe )

20151050

Tpeak (K)

Sample 1 Sample 2 Sample 3

3. Experimental result3. Experimental result

Page 61: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between H and TpeakRelation between H and Tpeak

1000

750

500

250

0

Field (

Oe )

20151050

Tpeak (K)

Sample 1 Sample 2 Sample 3

linear relationlinear relation

3. Experimental result3. Experimental result

Page 62: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between H and TpeakRelation between H and Tpeak

1000

750

500

250

0

Field (

Oe )

20151050

Tpeak (K)

Sample 1 Sample 2 Sample 3

E(L) ~ B (L) - qM

L3)1/2

HE(L) ~ B (L) - qM

L3)1/2

H

H ~ - qM

-1/2L-3/2kBT

peak + q

M

-1/2L-3/2B(L)H ~ - qM

-1/2L-3/2kBT

peak + q

M

-1/2L-3/2B(L)

barrier energybarrier energy Zeeman energyZeeman energy

Appearance of peak at kBT

peak ~ E(L)Appearance of peak at k

BT

peak ~ E(L)

Linear relation between H and Tpeak

Linear relation between H and Tpeak

Lh < DL

h < D

3. Experimental result3. Experimental result

Page 63: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between H and TpeakRelation between H and Tpeak

1000

750

500

250

0

Field (

Oe )

20151050

Tpeak (K)

Sample 1 Sample 2 Sample 3

deviation from linear relationdeviation from linear relation

3. Experimental result3. Experimental result

Page 64: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Relation between H and TpeakRelation between H and Tpeak

1000

750

500

250

0

Field (

Oe )

20151050

Tpeak (K)

Sample 1 Sample 2 Sample 3Deviation from linear relation between H and T

peakDeviation from linear relation between H and T

peak

Lh > DL

h > D

Estimation of Lh

Estimation of Lh

3. Experimental result3. Experimental result

Possible estimation of δ in Lh

~ h

-δPossible estimation of δ in L

h ~

h

Page 65: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

4. Summary of behavior of spin glass nanoparticle in magnetic field4. Summary of behavior of spin glass nanoparticle in magnetic field

1. SG domain size and the critical exponent can be evaluated.1. SG domain size and the critical exponent can be evaluated.

2. Field crossover length and the critical exponent can be evaluated.2. Field crossover length and the critical exponent can be evaluated.

Page 66: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

4. Summary of behavior of spin glass nanoparticle in magnetic field4. Summary of behavior of spin glass nanoparticle in magnetic field

1. SG domain size and the critical exponent can be evaluated.1. SG domain size and the critical exponent can be evaluated.

2. Field crossover length and the critical exponent can be evaluated.2. Field crossover length and the critical exponent can be evaluated.

Page 67: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Concluding remarksConcluding remarks

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Effect of bond perturbation appears through the decrease in overlap length.· Effect of bond perturbation appears through the decrease in overlap length.

· SG domain size, field crossover length and the corresponding exponent can be quantitatively evaluated using SG nanoparticle.

· SG domain size, field crossover length and the corresponding exponent can be quantitatively evaluated using SG nanoparticle.

Page 68: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Concluding remarksConcluding remarks

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Effect of bond perturbation appears through the decrease in overlap length.· Effect of bond perturbation appears through the decrease in overlap length.

· SG domain size, field crossover length and the corresponding exponent can be quantitatively evaluated using SG nanoparticle.

· SG domain size, field crossover length and the corresponding exponent can be quantitatively evaluated using SG nanoparticle.

Page 69: Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio University Yokohama, Japan.

Concluding remarksConcluding remarks

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Ambiguities in temperature perturbation can be removed using bond perturbation based on the photo illumination on SG semiconductor.

· Effect of bond perturbation appears through the decrease in overlap length.· Effect of bond perturbation appears through the decrease in overlap length.

· SG domain size, field crossover length and the corresponding exponents can be quantitatively evaluated using SG nanoparticle.

· SG domain size, field crossover length and the corresponding exponents can be quantitatively evaluated using SG nanoparticle.