Temperature dependent magnetization dynamics of magnetic nanoparticles

TL;DR

This paper investigates how temperature and magnetic anisotropy affect the magnetization switching dynamics of single-domain magnetic nanoparticles using an extended Landau-Lifshitz-Gilbert model.

Contribution

It introduces a theoretical framework incorporating finite temperature effects into the Landau-Lifshitz-Gilbert equation for nanoparticle spin dynamics.

Findings

Minimum switching field amplitudes depend on temperature and anisotropy.

Reversal times vary with damping and external field type.

Static and dynamic fields influence switching behavior differently.

Abstract

Recent experimental and theoretical studies show that the switching behavior of magnetic nanoparticles can be well controlled by external time-dependent magnetic fields. In this work, we inspect theoretically the influence of the temperature and the magnetic anisotropy on the spin-dynamics and the switching properties of single domain magnetic nanoparticles (Stoner-particles). Our theoretical tools are the Landau-Lifshitz-Gilbert equation extended as to deal with finite temperatures within a Langevine framework. Physical quantities of interest are the minimum field amplitudes required for switching and the corresponding reversal times of the nanoparticle's magnetic moment. In particular, we contrast the cases of static and time-dependent external fields and analyze the influence of damping for a uniaxial and a cubic anisotropy.