Lateral spin injection and detection through electrodeposited Fe/GaAs contacts

TL;DR

This paper reports a significant improvement in spin injection efficiency into GaAs using electrodeposited Fe/GaAs contacts, attributed to a naturally formed magnetic iron oxide layer acting as a spin-dependent tunnel barrier, opening new avenues for spintronic devices.

Contribution

The study demonstrates that electrodeposited Fe/GaAs contacts achieve much higher spin injection efficiencies than traditional ultra-high-vacuum methods, due to a naturally formed magnetic oxide layer.

Findings

Spin injection efficiencies are two orders of magnitude higher than previous methods.

The iron oxide layer acts as a spin-dependent tunnel barrier.

Electrodeposition offers a practical alternative for spintronic device fabrication.

Abstract

Efforts to achieve efficient injection of spin-polarized electrons into a semiconductor, a key prerequisite for developing electronics that exploit the electron's spin degree of freedom, have so far met with limited success. Here we report experimental studies of lateral spin injection and detection through electrodeposited Fe/GaAs tunnel contacts. We demonstrate spin injection efficiencies two orders of magnitude higher than for state-of-the-art contacts fabricated via ultra-high-vacuum methods, including those with MgO or Al2O3 tunnel barriers. To account for this enhancement, we propose that an iron oxide layer that forms at the Fe/GaAs interface during electrodeposition, being magnetic, acts as a tunnel barrier with a spin-dependent height, presenting quantum spin transport calculations for such systems. This serendipitous discovery of greatly enhanced efficiency of spin injection into GaAs via electrodeposited contacts introduces a promising new direction for the development of practical semiconductor spintronic devices.