Large and robust electrical spin injection into GaAs at zero magnetic field using an ultrathin CoFeB/MgO injector Article - Août 2014

S. Liang, T. Zhang, Philippe Barate, Pierre Renucci, J. Frougier, M. Vidal, B. Xu, H. Jaffrès, J. -M. George, X. Devaux, Michel Hehn, Xavier Marie, Stéphane Mangin, H. Yang, A. Hallal, M. Chshiev, Thierry Amand, H. Liu, D. Liu, X. Han, Z. Wang, Yuan Lu

S. Liang, T. Zhang, Philippe Barate, Pierre Renucci, J. Frougier, M. Vidal, B. Xu, H. Jaffrès, J. -M. George, X. Devaux, Michel Hehn, Xavier Marie, Stéphane Mangin, H. Yang, A. Hallal, M. Chshiev, Thierry Amand, H. Liu, D. Liu, X. Han, Z. Wang, Yuan Lu, « Large and robust electrical spin injection into GaAs at zero magnetic field using an ultrathin CoFeB/MgO injector  », Physical Review B : Condensed Matter and Materials Physics (1998-2015), août 2014, pp. 505 - 505. ISSN 1098-0121

Abstract

Binary information encoded within the spin of carriers can be transferred into corresponding right-or left-handed circularly polarized photons emitted from an active semiconductor medium via carrier-photon angular momentum conversion. In order to attain maximized spin injection at out-of-plane magnetic remanence, a number of material systems have been explored as possible solid-state spin injectors. However, the circular polarization (P-C) of emitted light was still limited at 3-4% at remanence. Here, we demonstrate a sizable electroluminescence circular polarization from a III-V-based spin light-emitting diode at zero magnetic field with a perpendicular spin injector consisting of an ultrathin CoFeB ferromagnetic layer (1.2 nm) grown on a MgO tunnel barrier (2.5 nm). The maximum value of P-C measured at zero field is as large as 20% at 25 K and still 8% at 300 K. These types of ultrathin perpendicular spin injectors are of great interest (i) to realize the electrical switching of the magnetization of the injector layer owing to the advanced spin-transfer torque properties of the CoFeB layer and (ii) to be directly embedded in optical cavities for spin lasers due to their very low optical absorption loss.

Voir la notice complète sur HAL

Actualités