Disorder-induced cubic phase in Fe$_2$-based Heusler alloys

TL;DR

This study uses first-principles calculations to reveal that chemical disorder stabilizes the cubic phase in Fe$_2$-based Heusler alloys, providing insights for synthesizing tetragonal phases for permanent magnet applications.

Contribution

It uncovers the role of chemical disorder in stabilizing the cubic phase, advancing understanding of Fe$_2$-based Heusler alloys' structural stability.

Findings

Chemical disorder stabilizes the cubic phase.

Agreement with recent experimental data.

Insights for synthesizing tetragonal phases.

Abstract

Based on first-principles electronic structure calculations, we analyze the chemical and magnetic mechanisms stabilizing the cubic phase in Fe$_2$-based Heusler materials, which were previously predicted to be tetragonal when being chemically ordered. In agreement with recent experimental data, we found that these compounds crystallize within the so-called "inverted" cubic Heusler structure perturbed by a certain portion of the intrinsic chemical disorder. Understanding these mechanisms is a necessary step to guide towards the successful future synthesis of the stable Fe$_2$-based tetragonal phases, which are very promising candidates for the fabrication of rare-earth-free permanent magnets.