Magnetic anisotropy and interface exchange coupling dependence of exchange bias in core/shell doubly inverted magnetic nanoparticles

摘要

Using the classical Heisenberg model and Monte Carlo simulation, we present a numerical study of the exchange bias effect in doubly inverted core/shell magnetic nanoparticles with spherical morphology. We mainly focus on the influence of the magnetic anisotropy, interface spin-spin exchange coupling and also shell thickness on the hysteresis behaviours of the system. Our results indicate that there exists a critical shell anisotropy acting in the system. Below this critical anisotropy value, bias field exhibits a steep decrease or increase depending on the considered shell thickness value. Moreover, we show that sign and magnitude of the exchange bias can be adjusted by changing the shell thickness of the nanoparticle, keeping the other system parameters fixed, especially for the strong interface coupling regime.