The wide bandgap semiconductor ZnO is interesting for spintronic applications because of its small spin-orbit coupling implying a large spin coherence length. Utilizing vertical spin valve devices with ferromagnetic electrodes (TiN/Co/ZnO/Ni/Au), we study the spin-polarized transport across ZnO in all-electrical experiments. The measured magnetoresistance agrees well with the prediction of a two spin channel model with spin-dependent interface resistance. Fitting the data yields spin diffusion lengths of 10.8 nm (2 K), 10.7 nm (10 K), and 6.2 nm (200 K) in ZnO, corresponding to spin lifetimes of 2.6 ns (2 K), 2.0 ns (10 K), and 31 ps (200 K).
REFERENCES
1.
G. A.
Prinz
, Science
282
, 1660
(1998
).2.
J. Y.
Fu
and M. W.
Wu
, J. Appl. Phys.
104
, 093712
(2008
).3.
D. D.
Awschalom
and N.
Samarth
, in Semiconductor Spintronics and Quantum Computation
, edited by D. D.
Awschalom
, D.
Loss
, and N.
Samarth
(Springer
, Berlin
, 2002
), pp. 147
–193
.4.
S.
Ghosh
, V.
Sih
, W. H.
Lau
, D. D.
Awschalom
, S.
Bae
, S.
Wang
, S.
Vaidya
, and G.
Chapline
, Appl. Phys. Lett.
86
, 232507
(2005
).5.
W. K.
Liu
, K. M.
Whitaker
, A. L.
Smith
, K. R.
Kittilstved
, B. H.
Robinson
, and D. R.
Gamelin
, Phys. Rev. Lett.
98
, 186804
(2007
).6.
N.
Janßen
, K. M.
Whitaker
, D. R.
Gamelin
, and R.
Bratschitsch
, Nano Lett.
8
, 1991
(2008
).7.
C.
Weier
, “Optische Untersuchung der Spindynamik und der elektrischen Spininjektion in Zinkoxid
,” Diploma thesis (RWTH Aachen, II. Physikalisches Institut, Lehrstuhl A
, 2010
).8.
M.
Opel
, J. Phys. D: Appl. Phys.
45
, 033001
(2012
).9.
Y.
Chen
, M.
Ren
, G.
Ji
, J.
Fang
, J.
Chen
, S.
Xiao
, S.
Xie
, Y.
Liu
, and L.
Mei
, Phys. Lett. A
303
, 91
(2002
).10.
G.
Ji
, Z.
Zhang
, Y.
Chen
, S.
Yan
, Y.
Liu
, and L.
Mei
, Acta Metall. Sinica (English)
22
, 153
(2009
).11.
K.
Shimazawa
, Y.
Tsuchiya
, T.
Mizuno
, S.
Hara
, T.
Chou
, D.
Miyauchi
, T.
Machita
, T.
Ayukawa
, T.
Ichiki
, and K.
Noguchi
, IEEE Trans. Mag.
46
, 1487
(2010
).12.
G.
Schmidt
, D.
Ferrand
, L. W.
Molenkamp
, A. T.
Filip
, and B. J.
van Wees
, Phys. Rev. B
62
, R4790
(2000
).13.
M. N.
Baibich
, J. M.
Broto
, A.
Fert
, F. N.
van Dau
, F.
Petroff
, P.
Etienne
, G.
Creuzet
, A.
Friederich
, and J.
Chazelas
, Phys. Rev. Lett.
61
, 2472
(1988
).14.
G.
Binasch
, P.
Grünberg
, F.
Saurenbach
, and W.
Zinn
, Phys. Rev. B
39
, 4828
(1989
).15.
M. A. M.
Gijs
and G. E. W.
Bauer
, Adv. Phys.
46
, 285
(1997
).16.
R.
Gross
, J.
Klein
, B.
Wiedenhorst
, C.
Höfener
, U.
Schoop
, J. B.
Philipp
, M.
Schonecke
, F.
Herbstritt
, L.
Alff
, Y.
Lu
, A.
Marx
, S.
Schymon
, S.
Thienhaus
, and W.
Mader
, Proc. SPIE
4058
, 278
(2000
).17.
W.
Martienssen
and H.
Warlimont
, Springer Handbook of Condensed Matter and Materials Data
(Springer
, Heidelberg
, 2005
).18.
V.
Talyansky
, S.
Choopun
, M. J.
Downes
, R. P.
Sharma
, T.
Venkatesan
, Y. X.
Li
, L. G.
Salamanca-Riba
, M. C.
Wood
, R. T.
Lareau
, and K. A.
Jones
, J. Mater. Res.
14
, 3298
(1999
).19.
H.
Ago
, Y.
Ito
, N.
Mizuta
, K.
Yoshida
, B.
Hu
, C. M.
Orofeo
, M.
Tsuji
, K. I.
Ikeda
, and S.
Mizuno
, ACS Nano
4
, 7407
(2010
).20.
Y.
Chen
, D. M.
Bagnall
, H.-J.
Koh
, K.-T.
Park
, K.
Hiraga
, Z.
Zhu
, and T.
Yao
, J. Appl. Phys.
84
, 3912
(1998
).21.
G.
Kästle
, H.
Boyen
, B.
Koslowski
, A.
Plettl
, F.
Weigl
, and P.
Ziemann
, Surf. Sci.
498
, 168
(2002
).22.
The linear behavior is expected in the tunneling regime. For higher currents, heating leads to non-linear I–V characteristics.
23.
See supplementary material at http://dx.doi.org/10.1063/1.4747321 for angle-resolved measurements.
24.
T.
Valet
and A.
Fert
, Phys. Rev. B
48
, 7099
(1993
).25.
A.
Fert
and H.
Jaffrès
, Phys. Rev. B
64
, 184420
(2001
).26.
C. E.
Moreau
, I. C.
Moraru
, N. O.
Birge
, and W. P.
Pratt
, Appl. Phys. Lett.
90
, 012101
(2007
).27.
J.
Bass
and W. P.
Pratt
, J. Magn. Magn. Mater.
200
, 274
(1999
).28.
L.
Piraux
, S.
Dubois
, A.
Fert
, and L.
Belliard
, Eur. Phys. J. B
4
, 413
(1998
).29.
J.
Bass
and W. P.
Pratt
, J. Phys.: Condens. Matter
19
, 183201
(2007
).30.
N. J.
Harmon
, W. O.
Putikka
, and R.
Joynt
, Phys. Rev. B
79
, 115204
(2009
).© 2012 American Institute of Physics.
2012
American Institute of Physics
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