Thermal fluctuations and longitudinal relaxation of single-domain magnetic particles at elevated temperatures

TL;DR

This paper investigates the switching times of magnetic nanoparticles at high temperatures near T_c, using the Landau-Lifshitz-Bloch model to account for magnetization magnitude relaxation, revealing shorter switching times than traditional models.

Contribution

It introduces a combined numerical and analytical approach based on the Landau-Lifshitz-Bloch equation to analyze thermal effects on magnetic particle switching times.

Findings

Switching times are shorter than predicted by naive models.

Magnetization magnitude relaxation significantly affects switching behavior.

Critical divergence of damping parameters influences relaxation dynamics.

Abstract

We present numerical and analytical results for the swiching times of magnetic nanoparticles with uniaxial anisotropy at elevated temperatures, including the vicinity of T_c. The consideration is based in the Landau-Lifshitz-Bloch equation that includes the relaxation of the magnetization magnitude M. The resulting switching times are shorter than those following from the naive Landau-Lifshitz equation due to (i) additional barrier lowering because of the reduction of M at the barrier and (ii) critical divergence of the damping parameters.