Enhanced exchange bias and improved ferromagnetic properties in Permalloy-BiFe0.95 Co0.05 O3 core-shell nanostructures

Abstract

Hybrid core-shell nanostructures consisting of permalloy (Ni80 Fe20) and multiferroic(BiFeO3, BFO/BiFe0.95 Co0.05 O3, BFC) materials were synthesized by a two-step method, based on wet chemical impregnation and subsequent electrodeposition within porous alumina membranes. Structural and magnetic characterizations have been done to investigate doping effect on magnetic properties and exchange bias. The magnetometry analysis revealed significant enhancements of the exchange bias and coercivity in NiFe-BFC core-shell nanostructures as compared with NiFe-BFO core-shell nanostructures. The enhancements can be attributed to the effective reduction of ferromagnet domain sizes between adjacent layers of core-shell structure. It indicates that it is possible to improve properties of multiferroic composites by site-engineering method. Our approach opens a pathway to obtain optimized nanostructured multiferroic composites exhibiting tunable magnetic properties.