Dielectric Spectroscopy Study Of The Ni0.2zn0.8fe2o4 Spinel Ferrite As A Function Of Frequency And Temperature

The resistance and the capacitance of Ni0.2Zn0.8Fe2O4 nanocrystalline ferrite prepared by solid state method were measured as a function of frequency in the range 50 Hz-10 MHz at various temperatures (340 K-600 K). The electrical and dielectric properties of spinel ferrite were determined and studied as a function of temperature. The decrease of real impedance values with the increase in frequency is explained using the model of Maxwell-Wagner interfacial polarization. We found that the relaxation time is strongly dependent on frequency and temperature. The impedance plane plots present three semicircle arcs associated to three different relaxation phenomena. Electrical equivalent circuit was determined to explain the dielectric measurements. Activation energies determined from both dc resistance and distribution of the relaxation times are similar. Frequency and temperature dependency of the giant dielectric constant values have been discussed using the model of charge carrier hopping.