Quantitative detection of electrically injected spin accumulation in GaAs using the magneto-optical Kerr effect

TL;DR

This study demonstrates the detection and quantification of electrically injected spin accumulation in GaAs using magneto-optical Kerr effect, providing insights into spin injection efficiency and concentration.

Contribution

It introduces an ultra sensitive Kerr rotation setup to measure spin injection from (Zn,Mn)Se into GaAs and quantifies the injected spin concentration.

Findings

Injected spin concentration is approximately 0.4×10^{15} cm^{-3} at 0.7 V bias.

Electrical spin injection can be reliably detected and distinguished from artifacts.

The method enables quantitative analysis of spin injection efficiency.

Abstract

Using an ultra sensitive magneto-optical Kerr rotation setup we have observed electrical spin injection from (Zn,Mn)Se into bulk GaAs and quantified the spin injection efficiency. The current induced contribution was carefully separated from possible artifacts and studied as a function of voltage and external magnetic field. Our measurements allow us to estimate the concentration of the electrically injected spins into GaAs to be approximately 0.4$\times10^{15}$cm$^{-3}$ at a reverse bias of 0.7 V.