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arXiv · 1404.4527

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

S. Liang·T. T. Zhang·P. Barate·J. Frougier·M. Vidal·P. Renucci·B. Xu·H. Jaffrès·J. M. George·X. Devaux·M. Hehn·X. Marie·S. Mangin·H. Yang·A. Hallal·M. Chshiev·T. Amand·H. Liu·D. Liu·X. Han·Z. Wang·Y. Lu
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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.

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S. Liang, T. T. Zhang, P. Barate, J. Frougier, M. Vidal, P. Renucci, B. Xu, H. Jaffrès, J. M. George, X. Devaux, M. Hehn, X. Marie, S. Mangin, H. Yang, A. Hallal, M. Chshiev, T. Amand, H. Liu, D. Liu, X. Han, Z. Wang, Y. Lu. 2014-04-17. Large and robust electrical spin injection into GaAs at zero magnetic field using an ultrathin CoFeB/MgO injector. https://doi.org/10.1103/physrevb.90.085310

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