Spin-polarization and electronic properties of half-metallic Heusler alloys calculated from first-principles

TL;DR

This paper reviews the electronic and magnetic properties of half-metallic Heusler alloys, emphasizing their potential for spintronic applications and analyzing factors affecting their half-metallicity.

Contribution

It provides a comprehensive first-principles analysis of the origin, stability, and robustness of half-metallicity in Heusler alloys, including effects of doping, disorder, and temperature.

Findings

High spin-polarization persists despite spin-orbit coupling.

Small doping and low-energy defects minimally affect the gap.

Temperature can rapidly destroy half-metallicity.

Abstract

Half-metallic Heusler alloys are amongst the most promising materials for future magnetoelectronic applications. We review some recent results on the electronic properties of these compounds. The origin of the gap in these half-metallic alloys and its connection to the magnetic properties are well understood. Changing the lattice parameter shifts slightly the Fermi level. Spin-orbit coupling induces states within the gap but the alloys keep a very high degree of spin-polarization at the Fermi level. Small degrees of doping and disorder as well as defects with low formation energy have little effect on the properties of the gap, while temperature effects can lead to a quick loss of half-metallicity. Finally we discuss two special issues; the case of quaternary Heusler alloys and the half-metallic ferrimagnets.