Magnetoelastic and Magnetostrictive Properties of Co$_2$XAl Heusler Compounds

TL;DR

This study uses first principles calculations to analyze the magnetoelastic and magnetostrictive properties of Co$_2$XAl Heusler compounds, introducing a torque method for efficient and detailed analysis of atomic contributions.

Contribution

It introduces a torque-based computational approach for magnetoelastic constants, providing more efficient and detailed atomic-level insights compared to traditional methods.

Findings

Magnetostriction constants agree with experimental data.

Main contributions arise from specific spin-orbit coupling matrix elements.

Torque method offers computational efficiency and atomic-level detail.

Abstract

We present a comprehensive first principles electronic structure study of the magnetoelastic and magnetostrictive properties in the Co-based Co$_2$XAl (X = V, Ti, Cr, Mn, Fe) full Heusler compounds. In addition to the commonly used total energy approach, we employ torque method to calculate the magnetoelastic tensor elements. We show that the torque based methods are in general computationally more efficient, and allow to unveil the atomic- and orbital-contributions to the magnetoelastic constants in an exact manner, as opposed to the conventional approaches based on second order perturbation with respect to the spin-orbit coupling. The magnetostriction constants are in good agreement with available experimental data. The results reveal that the main contribution to the magnetostriction constants, $\lambda_{100}$ and $\lambda_{111}$, arises primarily from the strained-induced modulation of the $\langle d_{x^2-y^2}|\hat{L}_z|d_{xy}\rangle$ and $\langle d_{z^2}|\hat{L}_x|d_{yz}\rangle$ spin orbit coupling matrix elements, respectively, of the Co atoms.