Highly-efficient electrical spin injection into semiconductors using a half-metal spin source

Abstract

Highly-efficient spin injection into semiconductors is indispensable for creating viable spintronic devices, such as a spin transistor or a spin laser. In this article, we will describe our recent research activities on highly-efficient spin injection into GaAs using a half-metallic spin source of a Co-based Heusler alloy. We demonstrated clear spin injection through the observation of a nonlocal spin-valve signal and a Hanle signal. Moreover, we demonstrated dynamic nuclear polarization using electron spins injected into GaAs. The maximum spin polarization of both electron spins and nuclear spins in the GaAs channel was larger in the sample with Co₂MnSi electrodes than that in the sample with CoFe electrodes.