Ab-initio description of the magnetic shape anisotropy due to the Breit interaction

TL;DR

This paper develops a quantum-mechanical approach incorporating the Breit-interaction into relativistic band structure calculations to better understand magnetic shape anisotropy, especially in layered transition metal systems.

Contribution

It introduces a fully relativistic method that coherently includes both spin-orbit coupling and Breit-interaction for calculating magnetic anisotropy.

Findings

Breit-interaction significantly affects magnetic anisotropy in layered systems

The new approach improves understanding of competing anisotropy sources

Application to transition metals demonstrates practical relevance

Abstract

A quantum-mechanical description of the magnetic shape anisotropy, that is usually ascribed to the classical magnetic dipole-dipole interaction, has been developed. This is achieved by including the Breit-interaction, that can be seen as an electronic current-current interaction in addition to the conventional Coulomb interaction, within fully relativistic band structure calculations. The major sources of the magnetic anisotropy, spin-orbit coupling and the Breit-interaction, are treated coherently this way. This seems to be especially important for layered systems for which often both sources contribute with opposite sign to the magnetic anisotropy energy. Applications to layered transition metal systems are presented to demonstrate the implications of this new approach in treating the magnetic shape anisotropy.