Highly spin-polarized room-temperature tunnel injector for semiconductor spintronics using MgO(100).

IBM Research Division, Almaden Research Center, San Jose, California 95120, USA.
Physical Review Letters (Impact Factor: 7.73). 03/2005; 94(5):056601. DOI: 10.1103/PhysRevLett.94.056601
Source: PubMed

ABSTRACT The spin polarization of current injected into GaAs from a CoFe/MgO(100) tunnel injector is inferred from the electroluminescence polarization from GaAs/AlGaAs quantum well detectors. The polarization reaches 57% at 100 K and 47% at 290 K in a 5 T perpendicular magnetic field. Taking into account the field dependence of the luminescence polarization, the spin injection efficiency is at least 52% at 100 K, and 32% at 290 K. We find a nonmonotonic temperature dependence of the polarization which can be attributed to spin relaxation in the quantum well detectors.

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