Ab initio prediction of half-metallic properties for the ferromagnetic Heusler alloys Co$_2$MSi (M=Ti, V, Cr)

TL;DR

This study uses density functional theory to predict that certain Co2MSi Heusler alloys are half-metallic ferromagnets with potential for high-temperature spintronic applications.

Contribution

It provides the first ab initio predictions of half-metallic properties for Co2MSi alloys, identifying stable and metastable phases with high Curie temperatures.

Findings

Co2TiSi, Co2VSi, and Co2CrSi are predicted to be half-metals.

Co2CrSi has a high density of majority spin states and a Curie temperature of 747K.

Co2TiSi and Co2VSi are thermodynamically stable, Co2CrSi is metastable.

Abstract

By means of density functional calculations the magnetic and electronic properties and phase stabilities of the Heusler compounds Co$_2$MSi (with M=Ti, V, Cr, Mn, Fe, Co, Ni) were investigated. Based on the calculated results we predict the ferromagnetic phases of the compounds Co$_2$TiSi, Co$_2$VSi and Co$_2$CrSi to be half-metals. Of particular interest is Co$_2$CrSi because of its high density of majority spin states at Fermi energy in combination with a reasonably high estimated Curie temperature of 747K. The compounds Co$_2$TiSi and Co$_2$VSi are thermodynamically stable, whereas Co$_2$CrSi is a metastable phase which might be stabilized by suitable experimental techniques.