Micromagnetic simulations of small arrays of submicron ferromagnetic particles

TL;DR

This paper uses micromagnetic simulations to analyze how dipolar and exchange interactions influence the ferromagnetic resonance spectra of small arrays of submicron ferromagnetic particles, revealing the effects of interparticle couplings.

Contribution

It provides a qualitative investigation of dipolar and exchange interactions in small particle arrays through resonance spectra analysis, highlighting the impact of interparticle couplings.

Findings

Magnetization precession shows amplitude mismatch due to dipolar interactions.

Exchange interactions significantly modify the spectra even with small contact surfaces.

Connected particles exhibit distinct resonance behaviors compared to isolated particles.

Abstract

We report the results of a set of simulations of small arrays of submicron ferromagnetic particles. The actions of dipolar and exchange interactions were qualitatively investigated by analysing the ferromagnetic resonance spectra at 9.37 GHz resulting from the magnetization response of con- nected and unconnected particles in the array as a function of the applied dc magnetic field. We find that the magnetization precession movement (at resonance) observed in individual particles in the array presents a distinctive behaviour (an amplitude mismatch) in comparison to isolated, one-particle reference simulations, a result that we attribute to the action of interparticle dipolar couplings. Exchange interactions appear to have an important role in modifying the spectra of connected particles, even through a small contact surface.