The behaviour of magnetic spherical particles and the heating effect in a rotating magnetic field via Brownian dynamics simulations

Abstract

The present study addresses the physical phenomena of a suspension composed of magnetic spherical particles in a rotating magnetic field in order to elucidate the influence of particle aggregation phenomena on the heat production from Brownian relaxation by means of Brownian dynamics simulations. In the case of a weak magnetic particle-particle interaction, particles do not aggregate to form specific cluster configurations. In this situation, the magnetic moment of each particle quickly inclines toward the field direction, and single particles do not give rise to a sufficiently large heating effect. With an increasing magnetic interaction between particles, chain-like clusters tend to form in the system and function to offer a larger resistance to the orientation of the magnetic moments, which leads to an increase in the heating effect. In the case of a significantly strong magnetic particle-particle interaction, the particles tend to aggregate to form stable ring-like clusters where the magnetic moments of the constituent particles are not able to be so responsive to the rotating magnetic field and this leads to a decrease in the heating effect. Highlights of the present paper The characteristics of particle aggregation have been clarified. The relationship between the strength of the magnetic particle-particle interaction and the frequency of the rotating magnetic field on the aggregation phenomena has been clarified. The response of the particle aggregates to an applied rotating magnetic field has been clarified. The relationship between the performance of the degree of heat production and the internal structure of magnetic particle configurations has been clarified.