Pressure dependence of the Curie temperature in Ni2MnSn Heusler alloy: A first-principles study

TL;DR

This study uses first-principles calculations to analyze how pressure affects the electronic structure, exchange interactions, and Curie temperature of Ni2MnSn Heusler alloy, revealing non-monotonous behavior and metamagnetic transitions.

Contribution

It provides a theoretical analysis of pressure effects on Curie temperature in Ni2MnSn, including atomic interchange impacts, extending understanding beyond experimental data.

Findings

Curie temperature increases with pressure up to 12 GPa

Non-monotonous pressure dependence of Tc observed

Metamagnetic transition predicted at high pressures

Abstract

The pressure dependence of electronic structure, exchange interactions and Curie temperature in ferromagnetic Heusler alloy Ni2MnSn has been studied theoretically within the framework of the density-functional theory. The calculation of the exchange parameters is based on the frozen--magnon approach. The Curie temperature, Tc, is calculated within the mean-field approximation by solving the matrix equation for a multi-sublattice system. In agrement with experiment the Curie temperature increased from 362K at ambient pressure to 396 at 12 GPa. Extending the variation of the lattice parameter beyond the range studied experimentally we obtained non-monotonous pressure dependence of the Curie temperature and metamagnetic transition. We relate the theoretical dependence of Tc on the lattice constant to the corresponding dependence predicted by the empirical interaction curve. The Mn-Ni atomic interchange observed experimentally is simulated to study its influence on the Curie temperature.