Simulation of Magnetization Switching in Nanoparticle Systems

TL;DR

This paper numerically investigates magnetization reversal in magnetic nanoparticles across various time scales, using stochastic Landau-Lifshitz and Monte Carlo methods to understand the effects of field strength and thermal fluctuations.

Contribution

It introduces a combined numerical approach to simulate magnetization switching in nanoparticles over a wide range of time scales and field conditions.

Findings

Spin precession dominates reversal at high fields.

Thermally assisted reversal occurs at lower fields.

Different mechanisms govern switching depending on field strength.

Abstract

Magnetization reversal in magnetic nanostructures is investigated numerically over time-scales ranging from fast switching processes on a picosecond scale to thermally activated reversal on a microsecond time-scale. A simulation of the stochastic Landau-Lifshitz equation of motion is used as well as a time quantified Monte Carlo method for the simulation of classical spin systems modeling magnetic Co nanoparticles. For field pulses larger than the Stoner-Wohlfarth limit spin precession effects govern the reversal behavior of the particle while for lower fields a magnetization reversal is only possible when it is assisted by thermal fluctuations.