Growth, strain and spin orbit torques in epitaxial NiMnSb films sputtered on GaAs

TL;DR

This study demonstrates current-induced spin torques in epitaxial NiMnSb films on GaAs, revealing their symmetry, efficiency, and relation to spin-orbit interactions, advancing understanding of spintronic materials.

Contribution

First demonstration of spin torques in epitaxial NiMnSb films on GaAs with detailed symmetry and efficiency analysis.

Findings

Spin torques exhibit symmetry consistent with spin-orbit interaction in tetragonally distorted NiMnSb.

Both field-like and damping-like torques are observed in all samples.

Torque efficiency is comparable to ferromagnetic metal/heavy metal bilayers.

Abstract

We report current-induced spin torques in epitaxial NiMnSb films on a commercially available epi-ready GaAs substrate. The NiMnSb was grown by co-sputtering from three targets using optimised parameter. The films were processed into micro-scale bars to perform current-induced spin-torque measurements. Magnetic dynamics were excited by microwave currents and electric voltages along the bars were measured to analyse the symmetry of the current-induced torques. We found that the extracted symmetry of the spin torques matches those expected from spin-orbit interaction in a tetragonally distorted half-Heusler crystal. Both field-like and damping-like torques are observed in all the samples characterised, and the efficiency of the current-induced torques is comparable to that of ferromagnetic metal/heavy metal bilayers.