Rare-earth impurities in Co$_2$MnSi: an opportunity to improve Half-Metallicity at finite temperatures

TL;DR

This study investigates how doping Holmium impurities into Co$_2$MnSi affects its electronic and magnetic properties, revealing potential ways to enhance half-metallicity at finite temperatures through selective impurity placement.

Contribution

It provides new insights into impurity effects on half-metallicity in Co$_2$MnSi, combining experimental data with DFT calculations to identify impurity site-specific impacts.

Findings

Holmium moments align antiparallel to transition metal moments.

Ho doping on Co sites introduces states in the minority spin gap.

Ho doping on Mn sites preserves half-metallicity.

Abstract

We analyse the effects of doping Holmium impurities into the full-Heusler ferromagnetic alloy Co$_2$MnSi. Experimental results, as well as theoretical calculations within Density Functional Theory in the "Local Density Approximation plus Hubbard U" framework show that the holmium moment is aligned antiparallely to that of the transition metal atoms. According to the electronic structure calculations, substituting Ho on Co sites introduces a finite density of states in the minority spin gap, while substitution on the Mn sites preserves the half-metallic character.