Enhanced electrical and magnetic functionality of Ni–Zn-co-doped CoFe2O4 rGO nanocomposites

Abstract

Enhancement in electrical and magnetic functionalities of rGO CoFe₂O₄ and Co_0.7Zn_0.3Fe_1.7Ni_0.3O₄ nanocomposites was identified compared to their spinel-type metal oxides. Moreover, changes in morphology that occurred during the formation of the composites were fabricated via a simple in situ hydrothermal route. Electron microscopic investigations confirmed that the microspheres of the metal oxides were constructed by porous nanolamellae comprising nanoparticles interconnected to form highly stable porous microspheres. Conversely, in rGO–CoFe₂O₄ and rGO–Co_0.7Zn_0.3Fe_1.7Ni_0.3O₄ composites, distorted spinel-type metal oxide spheres on rGO sheets were observed. Frequency-dependent conductivity increased with an increase in temperature, obeying Jonscher's power law and Koop's phenomenological theory. The resistance of ferrites decreased from ∼1.4 MΩ to 30 KΩ for their respective rGO-based nanocomposites. The hysteresis curves of all the compounds showed them to be isotropic, soft ferrimagnetic in nature. Furthermore, a 30–50% enhancement in the values of magnetic parameters of the ferrites occurred when they were interfaced with rGO sheets. This enhancement was probably due to the interfacial interaction of rGO with ferrites. Such enhancement may afford an advancement in the potential applications of these nanocomposites.