Montecarlo simulation of core-shell (antiferromagnetic / ferromagnetic) nanoparticles

G.A. BOCAN; E. DE BIASI; E. LIMA JR.; E. WINKLER; R.D. ZYSLER

Buenos Aires

Workshop; X Latin American Workshop on Magnetism, Magnetic Materials and their Applications (X LAW3M); 2013

LAW3M

Core-shell bimagnetic Nanoparticles (antiferromagnetic (AFM) = ferromagnetic (FM) ) are the focus of increasing interest, given their potential technological applications. New magnetic properties arise because of the interface exchange interaction between the magnetic phases. These properties include the increment of the effective magnetic anisotropy of the system and also, the presence of an exchange bias field. In this work, we present results of Montecarlo simulations of the magnetization hysteresis curves for nanoparticles constituted by an AFM core and a FM shell. The algorithm used is based in Metropolis, and modified to take into account the hysteresis. Our system is described by a minimal Hamiltonian which describes the Zeeman interaction, the anisotropy for both phases and the exchange interactions, including an interphase term. We have obtained numerical magnetization curves vs. both temperature and field in Zero-Field-Cooling and Field-Cooling conditions. We discuss how the interplay between the anisotropies of the magnetic phases and the exchange interaction between them affects the magnetic behaviour of the core-shell system.