Dynamics of magnetic charges in artificial spin ice

TL;DR

This paper presents a theoretical model for the magnetization dynamics in artificial spin ice, highlighting how domain walls and Coulomb interactions lead to avalanches during magnetization reversal.

Contribution

It introduces a novel theoretical framework describing how magnetic charges and domain walls drive magnetization dynamics in artificial spin ice.

Findings

Magnetization reversal involves domain walls with magnetic charges.

Avalanches occur due to Coulomb interactions between magnetic charges.

A critical field $H_c$ triggers charge emission at lattice junctions.

Abstract

Artificial spin ice has been recently implemented in two-dimensional arrays of mesoscopic magnetic wires. We propose a theoretical model of magnetization dynamics in artificial spin ice under the action of an applied magnetic field. Magnetization reversal is mediated by domain walls carrying two units of magnetic charge. They are emitted by lattice junctions when the the local field exceeds a critical value $H_c$ required to pull apart magnetic charges of opposite sign. Positive feedback from Coulomb interactions between magnetic charges induces avalanches in magnetization reversal.