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Spin-dependent electron transport in ferromagnet/semiconductor Schottky barrier structures

Published online by Cambridge University Press:  14 March 2011

Atsufumi Hirohata
Affiliation:
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, ENGLAND
Yong-Bing Xu
Affiliation:
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, ENGLAND
Christian M. Guertler
Affiliation:
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, ENGLAND
J. Anthony
Affiliation:
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, ENGLAND
C. Bland
Affiliation:
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, ENGLAND
Stuart N. Holmes
Affiliation:
Cambridge Research Laboratory, Toshiba Research Europe Limited, 260 Cambridge Science Park, Milton Road, Cambridge CB4 0WE, ENGLAND
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Abstract

Clear evidence for high efficiency spin-polarized electron transport across ferromagnet/semiconductor Schottky barrier interfaces was observed in Ni80Fe20/GaAs structures. Circularly polarized light was used to excite electrons with a spin polarization perpendicular to the film plane. At negative bias, an almost constant difference between the helicity-dependent photocurrent obtained for the magnetization parallel and perpendicular to the photon helicity was detected. An effective asymmetry, A, was also estimated from the helicity-dependent photocurrent difference, attributed to spin-polarized electron tunneling from GaAs to NiFe (spin filtering). A decreases with increasing photon energy, which is consistent with the energy-dependence of the asymmetry of photoexcited electrons in GaAs. Weak spin injection from NiFe to GaAs was seen at a bias corresponding to the Schottky barrier height, which is likely to occur via a ballistic process.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

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References

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