A two-step fabrication and characterization of 1D hybrid ferromagnetic-multiferroic Ni - BiFe_(1-x)Co_xO_3 core-shell nanostructures

摘要

Hybrid core-shell nanowires (NWs) with nickel as core and Co doped BiFeO3 (BFCO) as shell were synthesized by employing a two-step methodology. A noticeable exchange bias H-ex phenomenon has been observed which clearly demonstrated the antiferromagnetic functionality of BiFeO3 shell material, was also observed. Both coercivity and exchange bias has shown slight increase after Co doping in BFO. This increase might be due to reduction in domain sizes of ferromagnetic material between layers of core-shell nanowires. At lower temperatures, the super-paramagnetic contributions play very important role to contribute to the overall magnetic behavior of core-shell nanostructures. It has been observed that easy magnetization axis was aligned along the NWs' axis because of dominant shape anisotropy. Angular dependence of coercivity H-c has shown the coherent mode of magnetization reversal mechanism. This two-step methodology can be used to fabricate other similar hybrid nanostructures which can further be investigated for their possible implementation in device applications.