Magnetic hyperthermia: the influence of dipolar interactions in a magnetosome-like nanoparticle system

D. VALDÉS; C. RAMOS, E. DE BIASI, R.D. ZYSLER; E. LIMA JR.; R.D. ZYSLER

S.C. de Bariloche

Simposio; XXIII Latin American Symposium on Solid State Physics (XXIII SLAFES); 2018

SLAFES

In this work we present a study of dipolar interactions in a magnetosome-like nanoparticle system, and their in uence on hyperthermia experiments. We have modeled the system as a collection of identical nanoparticles arranged along randomly-oriented chains. We assume that the eective eld felt by a particle is mainly given by the interaction with other particles in the same chain. Due to the morphological characteristics of the samples, we have considered only Néel relaxation as the mechanism of energy absorption, discarding Brown relaxation mechanism. The magnetic behavior of the particles is described by a previous modelthat considers the eects of temperature, as well as the frequency of the eld swept in the experiment. In this model, which goes beyond the description of the linear response theory, the magnetic eld is corrected considering interparticle interactions. We have studied the parallel and perpendicular components of the dipolar magnetic eld regarding the external one. Our simulations showed that the particles corresponding to the ends of the chains feel eects due to the dipolar interactions dierent than those that the particles in the central part of the chains feel. This, in fact, implies important eects, which can be tuned, concerning the hysteresis of each nanoparticle and hyperthermia, as we have discussed in the conclusions of this work. One of the most important conclusions is the fact that the dipolar interaction in these kind of systems can help to improve the hyperthermia signicantly for nanoparticle systems which can originally be far from the ideal conditions for hyperthermia experiments.