Electrical injection of spin-polarized electrons and electrical detection of dynamic nuclear polarization using a Heusler alloy spin source

Abstract

We demonstrated electrical spin injection from a half-metallic Heusler alloy Co${}_{2}$MnSi electrode into a GaAs channel through observation of a spin-valve signal and a Hanle signal in the four-terminal nonlocal geometry. Furthermore, we electrically detected a nuclear field acting on electron spins, which was produced by the dynamic nuclear polarization, through observation of transient oblique Hanle signals. Samples with a Co${}_{2}$MnSi spin source exhibited higher spin-injection efficiency and a larger nuclear field compared to samples with a Co${}_{50}$Fe${}_{50}$ spin source, suggesting that the spin polarization of Co${}_{2}$MnSi is higher. This higher polarization is promising for realizing future spintronic devices and for understanding spin interactions as well as spin-dependent transport properties in a semiconductor channel.