Micromagnetic Simulations of Clusters of Nanoparticles with Internal Structure: Application to Magnetic Hyperthermia

Micromagnetic simulation results on dynamic hysteresis loops of clusters iron oxide nanoparticles (NPs) with internal structure composed nanorods are compared the widely used macrospin approximation. Such calculations allowing for nanorod-composed NPs is facilitated by a previously developed coarse-graining method based renormalization group approach. With focus applications to magnetic hyperthermia, we show that magnetostatic interactions improve heating performance in chains and triangles, reduce fcc arrangements. Hysteresis triangular systems complex not recovered within approximation, especially at smaller interparticle distances. For arrangements, approximation predicts loop area, contrast NP case. An investigation local individual macrospins reveals impact geometry their neighbors versus collective response, inhomogeneous clusters, further differences between simulating use Capturing physical thus important some applications.