First-principles calculations of spin spirals in Ni2MnGa and Ni2MnAl

TL;DR

This paper uses first-principles calculations to analyze spin spiral configurations in Ni2MnGa and Ni2MnAl, providing insights into their magnetic structures and Curie temperatures relevant for magnetic shape memory applications.

Contribution

It presents the first detailed non-collinear magnetic configuration analysis of these Heusler alloys using first-principles methods, including dispersion curves and magnetic moment variations.

Findings

Calculated ground state magnetic structures for Ni2MnGa and Ni2MnAl.

Estimated Curie temperatures align well with experimental data.

Identified key atomic contributions to magnetic properties.

Abstract

We report here non-collinear magnetic configurations in the Heusler alloys Ni2MnGa and Ni2MnAl which are interesting in the context of the magnetic shape memory effect. The total energies for different spin spirals are calculated and the ground state magnetic structures are identified. The calculated dispersion curves are used to estimate the Curie temperature which is found to be in good agreement with experiments. In addition, the variation of the magnetic moment as a function of the spiral structure is studied. Most of the variation is associated with Ni, and symmetry constraints relevant for the magnetization are identified. Based on the calculated results, the effect of the constituent atoms in determining the Curie temperature is discussed.