2D arrays of interacting magnetic nanoparticles

C. SOPRANO; G P SARACCO; M. A. BAB

Conferencia; IEEE virtual conference on magnetism, ATC-ATG; 2023

The magnetic response of a system of spherical, monodisperse nanoparticles (NPs) randomly distributed in two-dimensional, non-magnetic matrices was studied using Monte Carlo simulations. The Stoner-Wohlfarth (SW) model [1], including dipolar interactions between the NPs [2], was employed to describe the system energy. The hysteresis loops for different densities were obtained at different temperatures (T) assuming Néel’s relaxation [3]. When the dipolar interactions increased, a magnetization step-like behavior was observed at specific ranges of the external magnetic field values that can be related to local energy minima. The analysis of the obtained coercive field and remanent magnetization as functions of density revealed non-monotonic behavior at lower T. At higher T, both magnitudes increased with density from the zero-value predicted by the SW model. The results can be interpretedby means of the competition between individual and collective behavior due to intrinsic anisotropy and dipolar interactions, respectively.