A correlation between microstructural and impedance properties of MnFe2-xCoxO4 nanoparticles

A comprehensive study of physical properties and impedance analysis of MnFe2-xCoxO4 (x = 0.00, 0.40, 0.80, 1.20, 1.60, 2.00) nanoparticles prepared by citrate-nitrate method has been carried out. Structural analysis by Rietveld refinement indicated the formation of pure cubic structure with the space group Fd 3 m. The chemical composition and approximate grain size of the samples were determined by energy dispersive X-ray spectroscopy and field-emission scanning electron microscopy, respectively. The presence of Co has a strong influence on space charge modulation and affect the grain-boundary resistance. The results showed that sample x = 1.20 has less mobility, less polarizability, and therefore lower dielectric constant which is preferred for high frequency or power applications to minimize electric power loss. Impedance analysis demonstrate that small polaron hopping are responsible for the short-range translation hopping in conduction process of the samples (except for x = 1.60).