Magnetic moment of inertia within the breathing model

TL;DR

This paper introduces a first-principles theoretical model to calculate the magnetic moment of inertia in materials, successfully matching experimental data and revealing distinct electronic mechanisms from damping.

Contribution

It develops an ab initio torque-torque correlation model for magnetic inertia, applied to Fe, Co, and Ni, providing insights into its electronic origin.

Findings

Calculated magnetic inertia values agree with experiments.

Different electronic mechanisms underlie inertia and damping.

The model offers a fundamental understanding of magnetic relaxation properties.

Abstract

An essential property of magnetic devices is the relaxation rate in magnetic switching which strongly depends on the energy dissipation and magnetic inertia of the magnetization dynamics. Both parameters are commonly taken as a phenomenological entities. However very recently, a large effort has been dedicated to obtain Gilbert damping from first principles. In contrast, there is no ab initio study that so far has reproduced measured data of magnetic inertia in magnetic materials. In this letter, we present and elaborate on a theoretical model for calculating the magnetic moment of inertia based on the torque-torque correlation model. Particularly, the method has been applied to bulk bcc Fe, fcc Co and fcc Ni in the framework of the tight-binding approximation and the numerical values are comparable with recent experimental measurements. The theoretical results elucidate the physical origin of the moment of inertia based on the electronic structure. Even though the moment of inertia and damping are produced by the spin-orbit coupling, our analysis shows that they are caused by undergo different electronic structure mechanisms.