First order reversal curves simulation for core-shell nanoparticles via 3D-Ising model

We studied the magnetic properties of the 3D-Ising model employing Montecarlo simulations. The system is built with a cubic unit cell compound of spherical nanoparticles with a core-shell structure. We have recovered the dynamical magnetic properties such as the susceptibility, energy, heat capacity and equilibrium magnetization for Ferro and Anti-Ferro magnetic couplings. All these properties were studied as a function of nanoparticle size. We found a nanoparticle critical-size limit below which the magnetic properties depart from those of the bulk. In addition, in simulating first order reversal curves (FORC) of the core-shell structures, we found that we were able to identify features on the FORC diagram that allowed us to decouple individual magnetic reversal mechanisms of the core, shell and the interface. Our results suggest that nano-confinement modify bulk properties and that FORC is able to separate individual magnetic contributions to the magnetism that are otherwise hidden in the isothermal hysteresis loops.