experiments of sto synchronization by electrical connection · (mattana, af et al) as in this...

trilayer 1

1.0 1.1 1.2 1.30.0

0.1

0.2

0.3

0.4

0.5

0.6

po

we

r (p

W/G

Hz/m

A2

)

frequency (GHz)

- 9 mA

-12.4 mA

increasing I

1.0 1.1 1.2 1.3

0.0

0.1

0.2

0.3

0.4

0.5

0.6

po

we

r (p

W/G

Hz/m

A2)

frequency (GHz)

-11.00mA

-9.80mA

Idc Ihf1+

trilayer 2

Ihf2+

hf circuit

Ihf1+ Ihf2

Idc

Experiments of STO synchronization by electrical connection

(B.Georges, AF et al, CNRS/Thales and LPN-CNRS, preliminary results)

Spintronique avec semi-conducteurs

et molécules

GaMnAs (Tc→170K) and R.T. FS

Electrical control of ferromagnetism

TMR, TAMR, spin transfer (GaMnAs)

Field-induced metal/insulator transition

Spintronics with semiconductors

Magnetic metal/semiconductor

hybrid structures

Example: spin

injection from

Fe into LED

(Mostnyi et al,

PR. B 68, 2003)

Ferromagnetic

semiconductors (FS)

GaMnAs (Tc→170K) and R.T. FS

Electrical control of ferromagnetism

TMR, TAMR, spin transfer (GaMnAs)

Field-induced metal/insulator transition

Spintronics with semiconductors

Magnetic metal/semiconductor

hybrid structures

Example: spin

injection from

Fe into LED

(Mostnyi et al,

PR. B 68, 2003)

Ferromagnetic

semiconductors (FS)

F1 F2

Semiconductor

channel

V

Spin Field Effect Transistor ?

Semiconductor channel between

spin-polarized source and draintransforming spin information into

large (?) and tunable (by gate voltage) electrical signal

Nonmagnetic lateral channel between spin-polarized source and drain

Semiconductor channel:

« Measured effects of the order of 0.1-1% have been reported for the change in

voltage or resistance (between P and AP)…. », from the review article

« Electrical Spin Injection and Transport in Semiconductors » by BT Jonker

and ME Flatté in Nanomagnetism (ed.: DL Mills and JAC Bland, Elsevier 2006)

F1 F2

Semiconductor channel

PAP







Carbon nanotubes:

LSMO LSMO

LSMO = La2/3Sr1/3O3

nanotube

1.5 µµµµm

L.Hueso, N.D. Mathur,A.F. et al, Nature 445, 410, 2007

F1 F2


PAP







Carbon nanotubes:

∆∆∆∆R/R ≈≈≈≈ 60-70%, VAP-VP ≈≈≈≈ 60 mV

APAPAPAP

PPPP PPPPLSMO LSMO

LSMO = La2/3Sr1/3O3

nanotube

1.5 µµµµm


F1 F2


PAP

60%

MR=72 %







Carbon nanotubes:

∆∆∆∆R/R ≈≈≈≈ 60-70%, VAP-VP ≈≈≈≈ 60 mV

LSMO LSMO

LSMO = La2/3Sr1/3O3

nanotube

1.5 µµµµm


F1 F2


PAP

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition

dwell time ττττn < spin lifetime ττττsf

Condition for

spin injection

Nb rr /*

v

rL

vt

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

NsfNN

b

lr

r

ρ

γ

=

=

∝=

resistance interface theofasymmetry spin

teff1/trans.coresist.interfaceareaunit **r

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

F1 F2

Semiconductor

channel

V

L

F1 F2

Semiconductor

channel

V

L

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

LInterface resistance rb*

in most experimentsNsf

l

LNrbr <<*

Two interface

spin transportproblem (diffusive regime)

sfn ττ >>..,*ei

L

lrr

Nsf

Nb >>

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

al)etAF(Mattana,

examplethisinas

raszerotodrops

R

R

b

sfnP

*

22

/1

/1

)1/(

ττγγ

+−

=∆

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

F1 F2

Semiconductor

channel

V

L

F1 F2

Semiconductor

channel

V

L

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

Nsf

l

LNrbr <<*

Two interface spin transport

problem (diffusive regime)

b

Magnetic field (Oe)

1E-3 0.01 0.10

10

20

30

40

50

T=4K

GaAs QW=6nm

1.95nm1.45nm1.7nm

MR ( % )

b

Magnetic field (Oe)

1E-3 0.01 0.10

10

20

30

40

50

T=4K

GaAs QW=6nm

1.95nm1.45nm1.7nm

MR ( % )

)( 2* cmr b Ω

GaMnAs/AlAs/GaAs/AlAs/GaMnAs vertical structure

v

rL

vt

L

timedwell

b

r

n

*

*

2∝=τ

Carbon nanotubes between spin-polarized sources and drains

La2/3Sr1/3MnO3(LSMO)

La2/3Sr1/3MnO

3 (LSMO)

MR=72 %

PPPP PPPP

MR=60 %

L ≈ 1-2 µm

NanotubesNanotubesNanotubesNanotubes ((((also graphenealso graphenealso graphenealso graphene, , , , other moleculesother moleculesother moleculesother molecules) :) :) :) :

)(long2

)/10(long 317

sfr

n

sf

istv

Lsmallisvbut

cmelnforbecan

ττ

τ

>>=→

≈SemiconductorsSemiconductorsSemiconductorsSemiconductors::::

sfnsfn

Pif

R

RP

P

ττττγγ

<+

−=

∆

===

largeis,/1

)1/(),off(Aand(on)Pbetweencontrastthe:

Sinjectionγlifetime,spinτtime,dwellτ:drainandsourceSPbetweenTransport

22

sfn

)50(2

CNT)in50ns(long

sfr

n

sf

nsshortrelativelyistv

Lvvelocityhigh

islifetimespinorbitspinsmall

ττ

τ

≈≈=→

≈→−


)50(2

CNT)in50ns(long

sfr

n

sf


Lvvelocityhigh


ττ

τ

≈≈=→

≈→−

)(long2

)/10(long 317

sfr

n

sf

istv

Lsmallisvbut

cmelnforbecan

ττ

τ

>>=→


Solution for semiconductors:

shorter L ?, larger transmission tr ?

sfnsfn

Pif

R

RP

P

ττττγγ

<+

−=

∆

===

largeis,/1



22

sfn


)(long2

)/10(long 317

sfr

n

sf

istv

Lsmallisvbut

cmelnforbecan

ττ

τ

>>=→




Potential of molecular

spintronics (nanotubes,

graphene and others)

sfnsfn

Pif

R

RP

P

ττττγγ

<+

−=

∆

===

largeis,/1



22

sfn

)50(2

CNT)in50ns(long

sfr

n

sf


Lvvelocityhigh


ττ

τ

≈≈=→

≈→−


)(long2

)/10(long 317

sfr

n

sf

istv

Lsmallisvbut

cmelnforbecan

ττ

τ

>>=→




Potential of molecular



Next challenge for molecules:

spin control by gate

sfnsfn

Pif

R

RP

P

ττττγγ

<+

−=

∆

===

largeis,/1



22

sfn

)50(2

CNT)in50ns(long

sfr

n

sf


Lvvelocityhigh


ττ

τ

≈≈=→

≈→−

MR of LSMO/Alq3/Co structures (preliminary results)

Collaboration CNRS/Thales [C. Barraud, P. Seneor et al) and CNR Bologna (Dediu et al)]

Alq3 (50nm)

LSMO

Co

resist

1- 4 nm

Co nanocontact

≈≈≈≈10 nm

LSMO Co

Alq3

LUMO

HOMOAlq3 = π - conjugated 8-hydroxy-quinoline aluminium

ELECTRONIQUE

SPINTRONIQUE

Summary

¤Already important aplications of GMR/TMR (HDD, MRAM..) and now promising new fields

-Spin transfer formagnetic switching and microwave generation

-Spintronics with semiconductors, molecules or nanoparticles

M. Anane, C. Barraud, A. Barthélémy, H. Bea, A. Bernand-

Mantel, M. Bibes, O. Boulle, K.Bouzehouane, O. Copi, V.Cros,

C. Deranlot, B. Georges, J-M. George, J.Grollier, H. Jaffrès, S.

Laribi, J-L. Maurice, R. Mattana, F. Petroff, P. Seneor, M.

Tran F. Van Dau, A. Vaurès

Université Paris-Sud and Unité Mixte de Physique CNRS-Thales, Orsay, France

P.M. Levy, New York University, A.Hamzic, Zagreb University

B. Lépine, A. Guivarch and G. Jezequel

Unité PALMS, Université de Rennes , Rennes, France

G. Faini, R. Giraud, A. Lemaître: CNRS-LPN, Marcoussis, France

L. Hueso, N.Mathur, Cambridge

J. Barnas, M. Gimtra, I. Weymann, Poznan University

Acknowledgements to

J↑↑↑↑-J↓↓↓↓

J↑↑↑↑+J↓↓↓↓*

*

bNF

bF

rrr

rr

++

+=

γβDeviations from at large current density (drift effect)

= low current limit

current density

= deviations from

the low current limit (nondegenerate

semiconductor)

from Jaffrès and A.F.

(see also Yu and Flatté)

NMNMNMNM = = = = semiconductorsemiconductorsemiconductorsemiconductor

EF↑

Rasbah, PR B 2000

A.F-Jaffrès, PR B 2001

Spin accumulation ∆µ∆µ∆µ∆µ= EF↑↑↑↑-EF↓↓↓↓

NMsfl

FMsfl

z

EF↑

Current Spin Polarization (J↑↑↑↑-J↓↓↓↓)/(J↑↑↑↑+J↓↓↓↓)

FMFMFMFMspin dependent. interf.

resist. (ex:tunnel barrier)

EF↓↓↓↓

EF↑↑↑↑

Spin dependent drop of the

electro-chemical potential

Discontinuity increases the

spin accumulation in NM

re-balanced spin relaxations

in F and NM

extension of the spin-

polarized current into the

semiconductor

e-

NsfNNb lrr ρ=≈*

NsfNNb lrr ρ=>>*

Spin injection/extraction at a Semiconductor/FM interface

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface


NanotubesNanotubesNanotubesNanotubes::::

)(2

50ns)(long

sfr

n

sf

shortistv

Lvvelocityhigh


ττ

τ

<=→

≈→−sfn ττ >>

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface


)(long2

)/10(long 317

sfr

n

sf

istv

Lsmallisvbut

cmelnforbecan

ττ

τ

>>=→

≈

SemiconductorsSemiconductorsSemiconductorsSemiconductors::::sfn ττ >>

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface



shorter L ?, larger transmission tr ? sfb

r

nv

rL

tv

Lττ >>∝=

*

*

2

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface


sfb

r

nv

rL

tv

Lττ >>∝=

*

*

2Potential of molecular



AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface


Next challenge for molecules:

spin control by gate

sfn ττ >>Potential of molecular



NMNMNMNM FMFMFMFM

zone of spin accumulation

NMsfl

FMsfl

EF↑

EF↑↑↑↑(z)

Spin accumulation

∆µ∆µ∆µ∆µ= EF↑↑↑↑-EF↓↓↓↓

Spin current

= J↑↑↑↑-J↓↓↓↓

z

z

J↑↑↑↑-J↓↓↓↓

F Ms fl = spin diffusion length in F

= spin diffusion length in NMN Ms fl

N Ms fl

FMsfl

EF↓↓↓↓(z)

E

2/111)](3/[

−↓

−↑

+= λλλFsf

2/1)6/(

NNsf

λλ=

Description* : Boltzmann-type equation with a

distribution function in which the equilibrium

chemical potential is replaced by

, function of σσσσ and z

which leads to macroscopic equations**relating the charge and spin currents to a spin

dependent electro-chemical potential

µµµµσσσσ(z)= eV(z) + EFσσσσ(z)

to finally,after having also introduced the

interface resistance boundary counditions,

derive the profiles of the spin accumulation

and spin↑↑↑↑(spin↓↓↓↓) currents

*Valet and Fert, PR B 48, 7099, 1993.** the same as in Silsbee-Johnson and van Son et al

)(zEFσ0FE

Spin injection/extraction at a NM/FM interface (beyond ballistic range)

I < 0I < 0I < 0I < 0

Standard behavior (initial state = P, I < 0)

¤ switching at low field

¤ precession regime at high field

0.1

0.2

0 0.5 1

ϕ/πϕ/πϕ/πϕ/π

ττττ ϕϕ ϕϕ/(ħ

|I0|/|e

|)

P AP

Standard Standard Standard Standard angularangularangularangular dependencedependencedependencedependence(ex: (ex: (ex: (ex: CoCoCoCo////CuCuCuCu////CoCoCoCo))))

fixedfixedfixedfixed MMMM

mmmmϕϕϕϕ

APAPAPAP

PPPP

I < 0 , H = 0I < 0 , H = 0I < 0 , H = 0I < 0 , H = 0Switching Switching Switching Switching

from from from from P to APP to APP to APP to AP

I < 0I < 0I < 0I < 0

I > 0I > 0I > 0I > 0

APP

Torque on the free layer (Py) as a function of the angle between m(m(m(m(PyPyPyPy)))) and M(Co) for

Shorter SDL in the free layer, ex: Co8(fixed)/Cu10/Py8(free)

I < 0I < 0I < 0I < 0

I > 0I > 0I > 0I > 0

APP

J. J. J. J. BarnasBarnasBarnasBarnas, A. , A. , A. , A. FertFertFertFert. et al, . et al, . et al, . et al, Phys. Rev. B 2005, Mat.Sc.Eng. B126,271,2006

Spin transfer torque

I < 0I < 0I < 0I < 0

I > 0I > 0I > 0I > 0

APP

Shorter SDL in the free layer, ex: Co8(fixed)/Cu10/Py8(free)

I < 0I < 0I < 0I < 0

I > 0I > 0I > 0I > 0

APP

J. J. J. J. BarnasBarnasBarnasBarnas, A. , A. , A. , A. FertFertFertFert. et al, . et al, . et al, . et al, Phys. Rev. B 2005, Mat.Sc.Eng. B126,271,2006

Spin transfer torque


mmmmϕϕϕϕ

APAPAPAP

PPPP

0.1

0.2

0 0.5 1

ϕ/πϕ/πϕ/πϕ/π

ττττ ϕϕ ϕϕ/(ħ

|I0|/|e

|)

P AP

Standard Standard Standard Standard angularangularangularangular dependencedependencedependencedependence(ex: (ex: (ex: (ex: CoCoCoCo////CuCuCuCu////CoCoCoCo))))

I < 0 , H = 0I < 0 , H = 0I < 0 , H = 0I < 0 , H = 0Switching from Switching from Switching from Switching from

P to APP to APP to APP to AP

I < 0I < 0I < 0I < 0

I < 0 , I < 0 , I < 0 , I < 0 , inactiveinactiveinactiveinactive


mmmmϕϕϕϕ

APAPAPAP

PPPP

I >0 , H = 0 I >0 , H = 0 I >0 , H = 0 I >0 , H = 0 precessionprecessionprecessionprecession


mmmmϕϕϕϕ

APAPAPAP

PPPP

inversion

-6 -4 -2 0 2

14.4

15.0

dV

/dI

( ΩΩ ΩΩ)

I (mA)

High field (H>Hc)

Low field (H<Hc)

I>0

Switching from

AP to P

I<0

Switching from

P to AP

VSD

VG

e∆V = 25-500 meV

>> Coulomb energy

and level spacing,

K< T <120 K

drainsource

nanotube

Quasi-continuous DOS, same conditions

as for semiconductor or metallic channel

drainsource

nanotube

Uc=e2/2C

δE+Uc

e∆V ≈ 1 meV

Usual

conditions:

small bias

voltage

experiments

LSMO/CNT/LSMO:

higher voltage

experiments thanks to

large interface

resistances and small

V2/R heating at large V

Oscillatory variation of the conductance,

different signs of theMR depending on the

bias voltage and from sample to sample

PAP

MR=60% AP

P P

Vbias=25 mV

T = 5 K

CNT instead of semiconductor : LSMO/CNT/LSMO (Hueso, Mathur, Fert et al,

Nature,445, 440, 2007)

LSMO LSMO

LSMO = La2/3Sr1/3O3

Carbon nanotube (CNT)1.5 µµµµm (multi-wall)

MR=72 %

MR=45 %MR=54 %

other samples

MR=60%

MR

/MR

(5K

, 25

m)

rb* ≅≅≅≅70 MΩΩΩΩ

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

al)etAF(Mattana,

examplethisinas

raszerotodrops

R

R

b

sfnP

*

22

/1

/1

)1/(

ττγγ

+−

=∆

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

F1 F2

Semiconductor

channel

V

L

F1 F2

Semiconductor

channel

V

L

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

Nsf

l

LNrbr <<*

Two interface


b

Magnetic field (Oe)

1E-3 0.01 0.10

10

20

30

40

50

T=4K

GaAs QW=6nm

1.95nm1.45nm1.7nm

MR ( % )

b

Magnetic field (Oe)

1E-3 0.01 0.10

10

20

30

40

50

T=4K

GaAs QW=6nm

1.95nm1.45nm1.7nm

MR ( % )

)( 2* cmr b Ω

GaMnAs/AlAs/GaAs/AlAs/GaMnAs vertical structure

AF and Jaffrès

PR B 2001

+cond-mat

0612495, +

IEEE Tr.El.Dev. 54,5,921,2007

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

sfbn

b

sfnP

rfor

raszerotodrops

R

R

ττ

ττγγ

>>∝

+−

=∆

*

*

22

/1

/1

)1/(

Condition


Condition for

spin injection

Nb rr /*

v

rL

tv

L

timedwell

b

r

n

*

*

2∝=τ

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL

L

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

10-4

10-2

100

102

104

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

N

lSF=2µm

tN=20nm

tN=2µm

tN=200nm

rb

*////rN

∆∆ ∆∆R/R

P

Condition


Condition for

spin injection

Nb rr /*

∆R

/RP

1−∝L

lwindow

sf

1.6

1.2

0.8

0.4

0.0

L=20nmL


in most experiments

with semiconductors

and lateral channel

Nsf

l

LNrbr <<*

Two interface


sfn ττ >>F1 F2

Semiconductor

channel

V

L

F1 F2

Semiconductor

channel

V

L

experiments of sto synchronization by electrical connection · (mattana, af et al) as in this...

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