Magnetic relaxation in finite two-dimensional nanoparticle ensembles

TL;DR

This paper investigates the slow magnetic relaxation process in finite 2D nanoparticle ensembles with dipolar interactions, developing a numerical simulation method to analyze the effects of correlations and finite size on relaxation.

Contribution

A novel numerical simulation approach for magnetic relaxation in finite nanoparticle ensembles considering correlations and size effects.

Findings

Correlations significantly influence relaxation dynamics.

Finite size effects alter relaxation times.

Method effectively models slow magnetic relaxation.

Abstract

We study the slow phase of thermally activated magnetic relaxation in finite two-dimensional ensembles of dipolar interacting ferromagnetic nanoparticles whose easy axes of magnetization are perpendicular to the distribution plane. We develop a method to numerically simulate the magnetic relaxation for the case that the smallest heights of the potential barriers between the equilibrium directions of the nanoparticle magnetic moments are much larger than the thermal energy. Within this framework, we analyze in detail the role that the correlations of the nanoparticle magnetic moments and the finite size of the nanoparticle ensemble play in magnetic relaxation.