Calculating the transport properties of magnetic materials from first-principles including thermal and alloy disorder, non-collinearity and spin-orbit coupling

TL;DR

This paper presents a first-principles scattering formalism incorporating spin-orbit coupling, non-collinearity, and disorder to calculate transport properties of magnetic materials, validated by comparison with experimental data.

Contribution

It introduces a flexible density functional theory-based method that models inhomogeneous disordered magnetic alloys including thermal effects and spin dynamics.

Findings

Accurately predicts temperature-dependent resistivity of Permalloy.

Successfully reproduces experimental magnetization damping and its temperature dependence.

Demonstrates the method's capability to handle complex disordered magnetic systems.

Abstract

A density functional theory based two-terminal scattering formalism that includes spin-orbit coupling and spin non-collinearity is described. An implementation using tight-binding muffin-tin orbitals combined with extensive use of sparse matrix techniques allows a wide variety of inhomogeneous structures to be flexibly modelled with various types of disorder including temperature induced lattice and spin disorder. The methodology is illustrated with calculations of the temperature dependent resistivity and magnetization damping for the important substitutional disordered magnetic alloy Permalloy (Py), Ni$_{80}$Fe$_{20}$. Comparison of calculated results with recent experimental measurements of the damping (including its temperature dependence) indicates that the scattering approach captures the most important contributions to this important property.