A self-consistent spin-diffusion model for micromagnetics

TL;DR

This paper introduces a comprehensive 3D micromagnetic model that self-consistently couples magnetization dynamics with spin diffusion and electric potential, improving the accuracy of resistance change predictions in magnetic structures.

Contribution

It presents a novel self-consistent finite-element algorithm coupling Landau-Lifshitz-Gilbert and spin diffusion equations for micromagnetics.

Findings

Accurately models spin accumulation at interfaces and smooth transitions.

Validates the model with vortex motion simulations.

Demonstrates agreement with experimental multilayer resistivity data.

Abstract

We propose a three-dimensional micromagnetic model that dynamically solves the Landau-Lifshitz-Gilbert equation coupled to the full spin-diffusion equation. In contrast to previous methods, we solve for the magnetization dynamics and the electric potential in a self-consistent fashion. This treatment allows for an accurate description of magnetization dependent resistance changes. Moreover, the presented algorithm describes both spin accumulation due to smooth magnetization transitions and due to material interfaces as in multilayer structures. The model and its finite-element implementation are validated by current driven motion of a magnetic vortex structure. In a second experiment, the resistivity of a magnetic multilayer structure in dependence of the tilting angle of the magnetization in the different layers is investigated. Both examples show good agreement with reference simulations and experiments respectively.