Conductivity and giant permittivity study of Zn0.5Ni0.5Fe₂O₄ spinel ferrite as a function of frequency and temperature

Ni0.5Zn0.5Fe₂O₄ was prepared by the solid state reaction route at different temperatures. The dielectric properties of spinel ferrites were investigated in the frequency range 50 Hz-10 MHz and in the temperature range 300-420 K. Conductance is shown to increase with increasing frequency and temperature. Impedance analyses indicated that the relaxation phenomenon is strongly dependent on temperature and frequency. The impedance plots displayed both intra- and inter-granular contributions. Electrical equivalent circuit was proposed to explain the impedance results. The decrease of giant permittivity values with the increase in frequency proves the dispersion in the low frequency range and is showing the Maxwell-Wagner interfacial polarization.