Structural and electrical properties of zinc-substituted cobalt ferrite

Abstract

Polycrystalline samples of Co_1−xZn_xFe₂O₄ with stoichiometric proportion (x) varying from 0.0 to 1.0 were prepared through the thermal decomposition of their respective oxalates. The samples were calcined at 1000 °C for 3 h and characterized using X-ray diffraction (XRD) and Mössbauer spectroscopy techniques. The study of the cation distribution using Mössbauer spectroscopy showed that the ions at the tetrahedral site moved to the octahedral site by the addition of zinc and that the system varied from an inverse to a normal spinel structure. The values of the lattice parameter, X-ray density, oxygen parameter, inversion factor and radii of tetrahedral and octahedral sites were calculated using X-ray diffraction data. The temperature dependence of the conductivity showed a definite kink, except for the ZnFe₂O₄ sample, which can be attributed to the ferromagnetic–paramagnetic transitions. The calculated activation energy in the paramagnetic region was found to be smaller than that in the ferromagnetic region.