First-principles calculation of the intersublattice exchange interactions and Curie temperatures of full Heusler alloys Ni2MnX (X=Ga, In, Sn, Sb)

TL;DR

This study uses first-principles density-functional theory to calculate exchange interactions and Curie temperatures in Ni2MnX full Heusler alloys, revealing how different atomic interactions influence magnetic properties.

Contribution

It provides a detailed first-principles analysis of exchange interactions and Curie temperatures in Ni2MnX alloys, highlighting the roles of Mn-Mn and Mn-Ni interactions.

Findings

Good agreement with experimental Curie temperatures

Different exchange interactions significantly affect Tc

Mn-Ni and Mn-Mn interactions both influence magnetism

Abstract

The interatomic exchange interactions and Curie temperatures in Ni-based full Heusler alloys Ni2MnX with X=Ga, In, Sn and Sb are studied within the framework of the density-functional theory. The calculation of the exchange parameters is based on the frozen-magnon approach. Despite closeness of the experimental Curie temperatures for all four systems their magnetism appeared to differ strongly. This difference involves both the Mn-Mn and Mn-Ni exchange interactions. The Curie temperatures, Tc, are calculated within the mean-field approximation by solving a matrix equation for a multi-sublattice system. Good agreement with experiment for all four systems is obtained. The role of different exchange interactions in the formation of Tc of the systems is discussed.