Effects of the Magnetic Field on the Relaxation of Small Particle Systems

TL;DR

This paper investigates how magnetic fields influence the thermal relaxation behavior of small, non-interacting magnetic particles with varying anisotropy, using numerical simulations and a modified scaling approach to extract microscopic energy barrier information.

Contribution

It introduces a novel analysis method based on a modified $Tln(t/\tau_0)$ scaling to determine the field dependence of energy barriers in small particle systems.

Findings

Magnetic fields alter the relaxation curves of small particles.

The modified scaling allows extraction of microscopic energy barrier data.

Results demonstrate the method's effectiveness across different conditions.

Abstract

We study the effect of a magnetic field on the thermal relaxation of non-interacting small monodomain particle systems particles with a distribution of anisotropy constants and random easy-axes directions. Numerical calculations of the relaxation curves for different distribution widths, and under different magnetic fields $H$ and temperatures $T$, have been performed in the framework of a two-state approximation. We show how the obtained data can be analyzed in terms of an modified $Tln(t/\tau_0)$ scaling from which the field dependence of the mean relaxing energy barriers can be extracted, a microscopic information which is not easily obtainable by other methods.