Designing a fully-compensated half-metallic ferrimagnet

TL;DR

This paper combines theoretical calculations and experimental analysis to design a room-temperature compensated ferrimagnetic half-metallic material, Mn2RuxGa, by tuning composition and strain.

Contribution

It introduces a comprehensive approach integrating ab initio calculations and experiments to accurately model and design CFHMs, specifically Mn2RuxGa, considering disorder, defects, and doping.

Findings

Electronic doping is essential for half-metallicity.

Composition and strain can be optimized to achieve room-temperature CFHM.

Models accurately describe magnetic compensation and spin gap features.

Abstract

Recent experimental work on Mn2RuxGa demonstrates its potential as a compensated ferrimagnetic half-metal (CFHM).Here we present a set of high-throughput ab initio density functional theory calculations and detailed experimental characterisation, that enable us to correctly describe the nominal Mn2RuxGa thin films, in particular with regard to site-disorder and defects. We then construct models that accurately capture all the key features of the Mn-Ru-Ga system, including magnetic compensation and the spin gap at the Fermi level. We find that electronic doping is neccessary, which is achieved with a Mn/Ga ratio smaller than two. Our study shows how composition and substrate-induced biaxial strain can be combined to design the first room-temperature CFHM.