Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio...
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Transcript of Some experimental approaches to study the aging phenomena in spin glasses Tetsuya Sato Keio...
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
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
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
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
· 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
· 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
· 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
· 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.
· 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
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
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
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
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
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
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
· 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
· 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
· 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
· 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
· 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.
· 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.
· 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.
· 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)
· 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
· 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
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
· 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
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%
· 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
· 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
· 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
B. bond perturbationB. bond perturbation
no illumination tw
= 6000 secno illumination tw
= 6000 sec
B. bond perturbationB. bond perturbation
chaoticchaotic
accumulativeaccumulative
B. bond perturbationB. bond perturbation
· tpeak
· tpeak
B. bond perturbationB. bond perturbation
· tpeak
· tpeak accumulative aging
: tpeak
= tp + t
w
accumulative aging
: tpeak
= tp + t
w
B. bond perturbationB. bond perturbation
· tpeak
· tpeak
chaoticchaotic
accumulativeaccumulative
B. bond perturbationB. bond perturbation
· relative peak hight r· relative peak hight r
B. bond perturbationB. bond perturbation
· 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
· 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
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.
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
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
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
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
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.,
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 ···
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
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
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 ···
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
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
-δ
Droplet picture Droplet picture
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
Sample 1
Sample 2
Sample 3
D ~ 44 nm
D ~ 51 nm
D ~ 53 nm
2. Experimental procedure2. Experimental procedure
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
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
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
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
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
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
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
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
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
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
-δ
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.
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.
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.
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.
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.