Exchange Bias Effect in CoO@Fe₃O₄ Core–Shell Octahedron-Shaped Nanoparticles

Abstract

Increased\ncoercive and tunable exchange bias field values were\nregistered in hybrid CoO@Fe₃O₄ core–shell\noctahedron-shaped nanoparticles of different average size. In this\nstrained morphology, the metal cation chemical potentials at the interface\nbetween the antiferromagnetic and ferrimagnetic oxides become a very\ndynamic variable. This causes the effective magnetic anisotropy to\nincrease and the type of interface to change after growing the magnetite\nshell epitaxially onto the cobalt oxide {111} surface facets and,\nconsequently, to tune the exchange bias effect.