Dynamics of artificial spin ice: continuous honeycomb network

TL;DR

This paper models the magnetization dynamics in a honeycomb artificial spin ice, highlighting domain wall behavior, Coulomb interactions, and avalanche phenomena under external magnetic fields.

Contribution

It introduces a detailed model of magnetization dynamics in honeycomb artificial spin ice, emphasizing domain wall processes and Coulomb interactions, with analysis of reversal regimes and avalanches.

Findings

Identification of different magnetization reversal regimes

Observation of magnetic avalanches with 1/n length distribution

Role of Coulomb forces and disorder in system dynamics

Abstract

We model the dynamics of magnetization in an artificial analog of spin ice specializing to the case of a honeycomb network of connected magnetic nanowires. The inherently dissipative dynamics is mediated by the emission, propagation and absorption of domain walls in the links of the lattice. These domain walls carry two natural units of magnetic charge, whereas sites of the lattice contain a unit magnetic charge. Magnetostatic Coulomb forces between these charges play a major role in the physics of the system, as does quenched disorder caused by imperfections of the lattice. We identify and describe different regimes of magnetization reversal in an applied magnetic field determined by the orientation of the applied field with respect to the initial magnetization. One of the regimes is characterized by magnetic avalanches with a 1/n distribution of lengths.