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Spontaneous Spin Coherence in n-GaAs Produced by Ferromagnetic Proximity Polarization

R. J. Epstein·I. Malajovich·R. K. Kawakami·Y. Chye·M. Hanson·P. M. Petroff·A. C. Gossard·D. D. Awschalom
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Abstract

We find that photoexcited electrons in an n-GaAs epilayer rapidly (< 50 ps) spin-polarize due to the proximity of an epitaxial ferromagnetic metal. Comparison between MnAs/GaAs and Fe/GaAs structures reveals that this coherent spin polarization is aligned antiparallel and parallel to their magnetizations, respectively. In addition, the GaAs nuclear spins are dynamically polarized with a sign determined by the spontaneous electron spin orientation. In Fe/GaAs, competition between nuclear hyperfine and applied magnetic fields results in complete quenching of electron spin precession.

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R. J. Epstein, I. Malajovich, R. K. Kawakami, Y. Chye, M. Hanson, P. M. Petroff, A. C. Gossard, D. D. Awschalom. 2002-01-19. Spontaneous Spin Coherence in n-GaAs Produced by Ferromagnetic Proximity Polarization. https://doi.org/10.1103/physrevb.65.121202

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