Large and robust electrical spin injection into GaAs at zero magnetic field using an ultrathin CoFeB/MgO injector

Authors :: Liang, S.
Zhang, T. T.
Barate, P.
Frougier, J.
Vidal, M.
Renucci, P.
Xu, B.
Jaffrès, H.
George, J. M.
Devaux, X.
Hehn, M.
Marie, X.
Mangin, S.
Yang, H.
Hallal, A.
Chshiev, M.
Amand, T.
Liu, H.
Liu, D.
Han, X.
Wang, Z.
Lu, Y.
Publication Year :: 2014
Abstract: We demonstrate a large electrical spin injection into GaAs at zero magnetic field thanks to an ultrathin perpendicularly magnetized CoFeB contact of a few atomic planes (1.2 nm). The spin-polarization of electrons injected into GaAs was examined by the circular polarization of electroluminescence from a Spin Light Emitting Diode with embedded InGaAs/GaAs quantum wells. The electroluminescence polarization as a function of the magnetic field closely traces the out-of-plane magnetization of the CoFeB/MgO injector. A circular polarization degree of the emitted light as large as 20% at 25 K is achieved at zero magnetic field. Moreover the electroluminescence circular polarization is still about 8% at room temperature.<br />Comment: *Corresponding author: yuan.lu@univ-lorraine.fr

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