Modeling of the transitions between magnetic states of core/shell nanoparticles

Core/shell nanoparticles can be used in industry, medicine and biophysics, due to their unique properties. Theoretical studies of core/shell nanoparticles are mainly based on the Stoner-Wohlfarth model, and the Monte-Carlo simulation is mostly used the Metropolis algorithm. This method is an extension of one-phase nanoparticle model and not entirely correct for solving the magnetic states of core/shell nanoparticles, which represents a magnetic core covered with a magnetic or nonmagnetic shell. We developed a model of core/shell nanoparticles based on the analysis of total energy consisting of anisotropy energy Ea, magnetostatic interaction energy Em, exchange interaction energy Eex and energy of magnetic moment of the grain in external magnetic field Eh: E=Ea+Em+Eex+EH.