antiferromagnetic coulpling in spintronics tomas jungwirth univ. of nottingham, uk institute of...
Post on 03-Jan-2016
222 Views
Preview:
TRANSCRIPT
Antiferromagnetic coulpling in spintronicsAntiferromagnetic coulpling in spintronics
Tomas Jungwirth
Univ. of Nottingham, UK
Institute of Physics ASCR & Charles Univ., Czech Rep.
Hitachi and Univ. Cambridge, UK& Japan
Politecnico di Milano, Italy
Univ. of California, Berkeley
Institut de Ciencia de Materials de Barcelona, Spain
Giant magnetoresistance (GMR) multilayers: the dawn of spintronics
Fert, Grünberg, et al. 1988Nobel Prize 2007
Antiferromagnetic arrangement of a ferromagnetic multilayer at B=0
FM
FM
FM
FM
FM
FM
Soft FM
Hard FM
Soft FM
Hard FM
Fixed FM AFM
Soft FM
Fixed FMAFM
Soft FM
1. AFM coupling between FMs at B=0
3. One FM pinned by AFM material
Writing information in spin-valve: towards spintronic memory (MRAM)
2. One FM flips harder than the other FM
M
Kelvin, 1857
Ie
Read-out: Anisotropic magnetoresistance (AMR)Spintronic effect 150 years ahead of time
M
Ie
Kelvin, 1857
Read-out: Anisotropic magnetoresistance (AMR)Spintronic effect 150 years ahead of time
Ohmic AMR
Magnetization-orientation-dependent scatteringRelativistic spin-orbit coupling
Kelvin, 1857
Tunneling magnetoresistance (TMR)
MRAM
Spin-channel-dependent tunneling DOSNon-relativistic
Julliere 1975, Moodera et al., Miyazaki & Tezuka 1995
Tunneling anisotopic magnetoresistance (TAMR)
Gould, TJ et al. PRL ‘04
Magnetization-orientation-dependent tunneling DOSRelativistic spin-orbit coupling
“Mott“ two-spin-channel model of ferromagnets
“Dirac“ relativistic spin-orbit coupling
I
I I
I
Mott, 1936
Dirac, 1928
Two paradigms for spintronics
I
I I
I
Mott with ferromagnets
Dirac with ferromagnets Dirac with antiferromagnets
I I
I I
Mott with antiferromagnetsAntiferromagnetic MATERIALS playing ACTIVE role in spintronics
Fixed FMAFM
FM
FM
AFM
Ta/Ru/Ta
MnIr
MgO
Pt
NiFe
NiFe
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Ta/Ru/Ta
MnIr
MgO
Pt
NiFe
NiFe
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Spin-valve with AFM electrode
Ta/Ru/Ta
NiFe
MnIr
MgO
Pt
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Spin-valve with AFM electrode
Ta/Ru/Ta
NiFe
MnIr
MgO
Pt
>100% spin-valve-like signal at ~50 mT
50
100
R [
k]
-1 0 1
B [ T ]
1.5 & 3nm IrMn
4K
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Spin-valve with AFM electrode
Ta/Ru/Ta
NiFe
MnIr
MgO
Pt
Electrically measurable memory effect in AFM
-1000 -500 0 50020
40
60
80
R (
kohm
)Field (Oe)
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Spin-valve with AFM electrode
Ta/Ru/Ta
NiFe
MnIrMgOPt
Small signal in control sample without IrMn -100 -50 0 5020
40
60
80
R (
kohm
)
Field (mT)
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Spin-valve with AFM electrode
Scholl et al. PRL ‘04
See also Wang et al. PRL ’12: room-T AFM TAMR in CoPt/IrMn/AlOx/Pt
Spin-valve with AFM electrode
Writing by exchange-spring rotation of AFM by FM
B
[ o ]
50
100
R [k
]
-1 0 1B [ T ]
50
100
R [
k]
-1 0 1B [ T ]
-0.2 0 0.2Energy (eV)
50
-50
0
D
OS
/DO
S
spin-orbit coupling
AFM
Shick, TJ et al. PRB ’10see also Zemen, TJ et al. arXiv:1301.5369
Spin-valve with AFM electrode
-0.2 0 0.2Energy (eV)
50
-50
0
(DO
S00
1 –
DO
S11
0)/
DO
S
Shick, Wunderlich, TJ et al. PRB ‘10
IrMn, AuMn,...
Ferromagnets Antiferromagnets
Park, Wunderlich, Joo, Jung, Shin, TJ et al. PRL’08
Relativistic ab initio density-of-states anisotropy
Spin-valve with AFM electrode
Ta/Ru/Ta
MnIr
MgO
Pt
NiFe
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
AFM tunnel junction written by field-cool without FM
Ta/Ru/Ta
NiFe
MnIr
MgO
Pt
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
AFM tunnel junction written by field-cool without FM
MnIr
Pt
Field thermal-assisted MRAM
MgO
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
AFM tunnel junction written by field-cool without FM
Magnetic memory insensitive to magnetic fields & producing no stray fields
(RH-R
L)/
RL
(%)
MnIr
MgOPt
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
Bz
yx
AFM tunnel junction written by field-cool without FM
STT-MRAM
Spins injected from external polarizer in a non-uniform magnetic structure
Berger PRB ’96, Slonczewski JMMM ’96
MpM
Ie
Writing by current: non-relativistic spin-transfer torque
Spins injected from external polarizer in a non-uniform magnetic structure
I I
Mott with ferromagnets
I I
Mott with antiferromagnets
MpM
Ie
Berger PRB ’96, Slonczewski JMMM ’96
Writing by current: non-relativistic spin-transfer torque
M
Ie
Writing by current: relativistic spin-orbit torque
Manchon & Zhang, PRB ‘08, Chernyshev et al. Nature Phys.‘09, Miron et al. Nature Mater. ‘10, Fang, Ferguson, TJ et al. Nature Nanotech.‘11
Miron et al., Nature ‘11
Spin current in a uniform magnetic structure without external polarizer
In-plane current switching
Manchon & Zhang, PRB ‘08, Chernyshev et al. Nature Phys.‘09, Miron et al. Nature Mater. ‘10, Fang, Ferguson, TJ et al. Nature Nanotech.‘11
Spin current in a uniform magnetic structure without external polarizer
I I
Dirac with ferromagnets Dirac with antiferromagnets
I I
M
Ie Andrew Ferguson, W18.00007
Writing by current: relativistic spin-orbit torque
M
Spintronics & transistors Spintronics & photonics
Tc < room-T
Ohno, Dietl et al., Science ’98,’00, TJ et al., Rev. Mod. Phys. ‘06
Petr Němec, R18.00001
FM semiconductors
Writing by electric field or light: Magnetic semiconductor spintronics
II-VI FM TC (K) AFM TN (K)
MnO 122
MnS 152
MnSe 173
MnTe 323
EuO 67
EuS 16
EuSe 5
EuTe 10
II-V-IV-V FM TC (K) AFM TN (K)
MnSiN2 490
III-V FM TC (K) AFM TN (K)
FeN 100
FeP 115
FeAs 77
FeSb 100-220
GdN 72
GdP 15
GdAs 19
GdSb 27
I-VI-III-VI FM TC (K) AFM TN (K)
CuFeO2 11
CuFeS2 825
CuFeSe2 70
CuFeTe2 254
I-II-V FM TC (K) AFM TN (K)
Ia=Li, Na,..Ib=CuII=MnV=Sb,As, P
> room T
Semiconductors: more AFMs than FMs and high-TN AFMs
TJ, Novák, Martí et al. PRB ’11, Cava Viewpoint, Physics ’11, Máca, Mašek, TJ et al. JMMM ’12
Spin-orbit-coupled Mott AFM semiconductor
Kim et al., Science ’09, Jin et al. PRB ‘09, Arita et al. PRL ‘12
0 90 180 270 360-1
0
1
R
/R (
%)
0 90 180 270 360-1
0
1
0 90 180 270 360-1
0
1
R
/R (
%)
0 90 180 270 360-1
0
1
0 90 180 270 360-1
0
1
(°)
R
/R (
%)
0 90 180 270 360-1
0
1
(°)
LSMO
SIO Ag
Pt
LSMO
SIO AgAg
T = 200 KT = 200 K
T = 40 KT = 40 K
T = 4.2 K
T = 4.2 K
0 100 200 3000
1000
2000
3000
T (K)
R (
)
R13
R23
-20 0 20
-10
0
10
V (mV)
I (
A)
T = 4.2 K
Ohmic AMR in Sr2IrO4 AFM semiconductor
Xavier Martí, T18.00011
B.G. Park, J. Wunderlich, X. Marti, V. Holy, Y. Kurosaki, M. Yamada, H. Yamamoto, A. Nishide, J. Hayakawa, H. Takahashi, A.B. Shick, T. Jungwirth Nature Mater. 10 (2011) 347 – 351
X. Marti, B. G. Park, J. Wunderlich, H. Reichlova, Y. Kurosaki, M. Yamada, H. Yamamoto, A. Nishide, J. Hayakawa, H. Takahashi, T. Jungwirth Phys. Rev. Lett. 108 (2012) 017201(1) - 017201(4)
D. Petti, E. Albisetti, H. Reichlová, J. Gazquez, M. Varela, M. Molina-Ruiz, A. F. Lopeandía, K. Olejník, V. Novák, I. Fina, B. Dkhil, J. Hayakawa, X. Marti, J. Wunderlich, T. Jungwirth, R. Bertacco submitted to Appl. Phys. Lett.
Metal AFM spintronicsMetal AFM spintronics
Semiconductor AFM spintronicsSemiconductor AFM spintronics
T. Jungwirth, V. Novák, X. Marti, M. Cukr, F. Máca, A.B. Shick, J. Mašek, P. Horodyska, P. Němec, V. Holý, J. Zemek, P. Kužel, I. Němec, B. L. Gallagher, R. P. Campion, C. T. Foxon, J. Wunderlich Phys. Rev. B 83 (2011) 035321(1) - 035321(6).
C. Rayan Serrao, Jian Liu, J.T. Heron, G. Singh-Bhalla, A. Yadav, S.J. Suresha, R. J. Paull, D. Yi, J.-H. Chu, M. Trassin, A. Vishwanath, E. Arenholz, C. Frontera, J. Železný, J. Mašek, T. Jungwirth, X. Marti, R. Ramesh Phys. Rev. B 87 (2013) 085121(1)-08512(6)
P. Wadley, V. Novak, R. P. Campion, C. Rinaldi, X. Mart, H. Reichlova, J. Zelezny, J. Gazquez, M. A. Roldan, M. Varela, D. Khalyavin, S. Langridge, D. Kriegner,10 F. Maca, J. Masek, V. Holy, A. W. Rushforth, K. W. Edmonds, B. L. Gallagher, C. T. Foxon, J. Wunderlich, and T. Jungwirth, to be published
X. Marti, I. Fina, D. Yi, J. Liu, J.H. Chu, C. Rayan-Serrao, S. Suresha, J. Železný, T. Jungwirth, J. Fontcuberta, R. Ramesh, to be published
top related