Transcript talk-Baltimore-13

Antiferromagnetic coulpling in spintronics
Tomas Jungwirth
Institute of Physics ASCR
& Charles Univ., Czech Rep.
Politecnico di Milano, Italy
Univ. of Nottingham, UK
Hitachi and Univ. Cambridge, UK
& Japan
Institut de Ciencia de Materials Univ. of California, Berkeley
de Barcelona, Spain
Giant magnetoresistance (GMR) multilayers: the dawn of spintronics
Fert, Grünberg, et al. 1988
Nobel Prize 2007
Antiferromagnetic arrangement of a ferromagnetic multilayer at B=0
Writing information in spin-valve: towards spintronic memory (MRAM)
1. AFM coupling between FMs at B=0
FM
FM
FM
FM
FM
FM
2. One FM flips harder than the other FM
Soft FM
Soft FM
Hard FM
Hard FM
3. One FM pinned by AFM material
Soft FM
Soft FM
Fixed FM
AFM
Fixed FM
AFM
Towards reliable switching of a particular MRAM bit
Soft FM
NM
Fixed FM
AFM
Toggle switching  first commercial MRAMs
“Synthetic AFM“
FM
FM
Fixed FM
AFM
Read-out: Giant magnetoresistance (GMR)
Ie
Ie
Fert, Grünberg, et al. 1988
Nobel Prize 2007
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
M
Ie
Kelvin, 1857
Ohmic AMR
Kelvin, 1857
Magnetization-orientation-dependent scattering
Relativistic spin-orbit coupling
Ohmic GMR
Fert, Grünberg, 1988
Spin-channel-dependent scattering
Non-relativistic
Tunneling magnetoresistance (TMR)
Julliere 1975, Moodera et al., Miyazaki & Tezuka 1995
MRAM
Spin-channel-dependent tunneling DOS
Non-relativistic
Tunneling anisotopic magnetoresistance (TAMR)
Gould, TJ et al. PRL ‘04
Magnetization-orientation-dependent tunneling DOS
Relativistic spin-orbit coupling
Two paradigms for spintronics
“Mott“ two-spin-channel model of ferromagnets
I
I
Mott, 1936
“Dirac“ relativistic spin-orbit coupling
I
Dirac, 1928
I
Antiferromagnetic MATERIALS playing ACTIVE role in spintronics

Mott with antiferromagnets
Mott with
ferromagnets
I
I
I
Dirac with ferromagnets
I
Dirac with antiferromagnets
I
I
I
FM
FM
Fixed FM
AFM
AFM
I
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Pt
NiFe
MgO
NiFe
MnIr
Ta/Ru/Ta
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Pt
MgO
NiFe
MnIr
Ta/Ru/Ta
NiFe
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Pt
MgO
MnIr
NiFe
Ta/Ru/Ta
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
100
1.5 & 3nm IrMn
R [k]
Pt
MgO
MnIr
50
NiFe
Ta/Ru/Ta
-1
4K
0
B[T]
1
>100% spin-valve-like signal at ~50 mT
Spin-valve with AFM electrode
Pt
MgO
MnIr
R (kohm)
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
80
60
40
NiFe
Ta/Ru/Ta
20
-1000
-500
0
Field (Oe)
500
Electrically measurable memory effect in AFM
Spin-valve with AFM electrode
Park, Marti, Wunderlich,TJ et al. Nature Mat. ’11, PRL ’12
Pt
MgO
MnIr
NiFe
R (kohm)
Ta/Ru/Ta
80
60
40
20
-100
-50
0
Field (mT)
50
Small signal in control sample without IrMn
Spin-valve with AFM electrode
Writing by exchange-spring rotation of AFM by FM
Scholl et al. PRL ‘04
B
R [k]
100
50
-1
[o]
0
B[T]
See also Wang et al. PRL ’12: room-T AFM TAMR in CoPt/IrMn/AlOx/Pt
1
Spin-valve with AFM electrode
AFM
Shick, TJ et al. PRB ’10
see also Zemen, TJ et al.
arXiv:1301.5369
 DOS/DOS
50
R [k]
100
50
-1
0
B[T]
0
spin-orbit
coupling
1
-50
-0.2
0
Energy (eV)
0.2
Spin-valve with AFM electrode
Relativistic ab initio density-of-states anisotropy
(DOS001 – DOS110)/DOS
Antiferromagnets
Ferromagnets
50
IrMn, AuMn,...
0
-50
-0.2
0
Energy (eV)
Shick, Wunderlich, TJ et al. PRB ‘10
0.2
Park, Wunderlich, Joo, Jung, Shin, TJ et al. PRL’08
AFM tunnel junction written by field-cool without FM
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
Pt
MgO
MnIr
NiFe
Ta/Ru/Ta
AFM tunnel junction written by field-cool without FM
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
Pt
MgO
MnIr
NiFe
Ta/Ru/Ta
AFM tunnel junction written by field-cool without FM
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
Pt
MgO
MnIr
Ta/Ru/Ta
Field thermal-assisted MRAM
AFM tunnel junction written by field-cool without FM
Petti, Marti, Bertacco, TJ et al., submitted to APL ‘13
z
Pt
MgO
B
x
y
MnIr
(RH-RL)/RL (%)
Ta/Ru/Ta
Magnetic memory insensitive to magnetic fields & producing no stray fields
Writing by current: non-relativistic spin-transfer torque
Spins injected from external polarizer in a non-uniform magnetic structure
Mp
M
Ie
Berger PRB ’96, Slonczewski JMMM ’96
STT-MRAM
Writing by current: non-relativistic spin-transfer torque
Spins injected from external polarizer in a non-uniform magnetic structure
Mp
M
Ie
Berger PRB ’96, Slonczewski JMMM ’96
Mott with ferromagnets
I
I
Mott with antiferromagnets
I
I

Writing by current: relativistic spin-orbit torque
Spin current in a uniform magnetic structure without external polarizer
M
Ie
Manchon & Zhang, PRB ‘08, Chernyshev et al. Nature Phys.‘09,
Miron et al. Nature Mater. ‘10, Fang, Ferguson, TJ et al. Nature Nanotech.‘11
In-plane current switching
Miron et al., Nature ‘11
Writing by current: relativistic spin-orbit torque
Spin current in a uniform magnetic structure without external polarizer
M
Ie
Andrew Ferguson, W18.00007
Manchon & Zhang, PRB ‘08, Chernyshev et al. Nature Phys.‘09,
Miron et al. Nature Mater. ‘10, Fang, Ferguson, TJ et al. Nature Nanotech.‘11
Dirac with ferromagnets
I
Dirac with antiferromagnets
I
I
I
Writing by electric field or light: Magnetic semiconductor spintronics
Spintronics & transistors
Spintronics & photonics
M
Petr Němec, R18.00001
FM semiconductors
Tc < room-T
Ohno, Dietl et al., Science ’98,’00, TJ et al., Rev. Mod. Phys. ‘06
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
AFM TN (K)
III-V
MnO
122
FeN
100
MnS
152
FeP
115
MnSe
173
FeAs
77
MnTe
323
FeSb
100-220
II-VI
FM TC (K)
FM TC (K)
AFM TN (K)
EuO
67
GdN
72
EuS
16
GdP
15
EuSe
5
GdAs
19
EuTe
10
GdSb
27
AFM TN (K)
II-V-IV-V
CuFeO2
11
MnSiN2
CuFeS2
825
I-II-V
CuFeSe2
70
CuFeTe2
254
Ia=Li, Na,..
Ib=Cu
II=Mn
V=Sb,As, P
I-VI-III-VI
FM TC (K)
FM TC (K)
AFM TN (K)
490
FM TC (K)
AFM TN (K)
> room T
Spin-orbit-coupled Mott AFM semiconductor
Kim et al., Science ’09, Jin et al. PRB ‘09, Arita et al. PRL ‘12
Ohmic AMR in Sr2IrO4 AFM semiconductor
Xavier Martí, T18.00011
Pt
SIO
Ag
Ag
LSMO
R/R (%)
1
T = 200 K
0
-1
0
0
90 180 270 360
R/R (%)
1
R13
1000
0
-10
-20
0
0
0
V (mV)
100
200
T (K)
20
0
90 180 270 360
0
90 180 270 360
0
90 180 270 360
 (°)
0
0
90 180 270 360
T = 4.2
K
0
-1
300
0
1
1
T = 4.2 K
R/R (%)
10
I (A)
R ()
2000
-1
T = 40 K
-1
R23
Ag
LSMO
1
3000
SIO
-1
1
0
0
90 180 270 360
 (°)
-1
Metal AFM spintronics
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.
Semiconductor 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