Epitaxial growth and magnetic properties of NiMnAs film on GaAs substrate

TL;DR

This study demonstrates the successful epitaxial growth of NiMnAs films on GaAs substrates, revealing their magnetic properties and the influence of growth temperature, with implications for half-metallicity in spintronic applications.

Contribution

It reports the first epitaxial growth of NiMnAs on GaAs and analyzes how growth temperature affects magnetic properties and electronic structure.

Findings

Optimal growth temperature is ~370°C.

High Curie temperature and magnetic anisotropy achieved.

Magnetic properties linked to Mn electronic structure variations.

Abstract

Single-phase Ni0.46Mn0.54As films with strained C1b symmetry have been successfully grown on GaAs (001) substrates by molecular-beam epitaxy. The epitaxial relationship between the film and the substrate has been studied using synchrotron radiation, and a preferred configuration of (110)-orientated Ni0.46Mn0.54As on (001)-orientated GaAs was revealed. In addition, the magnetic properties of the films were found to be significantly influenced by the growth temperature. The optimized growth temperature is determined to be ~370 degree Celsius , for which relatively high Curie temperature, large saturation magnetization and coercive field, as well as the pronounced in-plane magnetic anisotropy were obtained. According to the results of X-ray absorption spectroscopy, the above phenomenon can be attributed to the variation of the local electronic structure of the Mn atoms. Our work provides useful information for the further investigations of NiMnAs, which is theoretically predicted to host robust half-metallicity.