Uniform and non-uniform thermal switching of magnetic particles

TL;DR

This paper investigates thermal switching behaviors of magnetic nanoparticles, analyzing uniform and non-uniform energy barriers, and explores the validity of simplified models using pulse-noise simulations and variational methods.

Contribution

It introduces a pulse-noise computational approach to study thermally-activated escape in magnetic particles, including non-uniform barriers and finite chains, advancing understanding of magnetic switching mechanisms.

Findings

Validated pulse-noise method for magnetic escape simulations

Derived barriers for non-uniform escape in elongated particles

Analyzed stability and crossover between barrier states

Abstract

The pulse-noise approach to systems of classical spins weakly interacting with the bath has been applied to study thermally-activated escape of magnetic nanoparticles over the uniform and nonuniform energy barriers at intermediate and low damping. The validity of approximating a single-domain particle by a single spin is investigated. Barriers for a non-uniform escape of elongated particles for the uniaxial model with transverse and longitudinal field have been worked out. Pulse-noise computations have been done for finite magnetic chains. The linear stability of the uniform barrier state has been investigated. The crossover between uniform and nonuniform barrier states has been studied with the help of the variational approach.