Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

The electrical properties of Ni0.27Cu0.10Zn0.63Fe2O4 (NCZF) prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus spectroscopy. We studied frequency and temperature dependencies of impedance and electric modulus of NCZF in a wide frequency range (20 Hz-5 MHz) at different measuring temperatures T-SM (30-225 degrees C). The complex impedance spectra clearly showed both grain and grain boundary effects on the electrical properties. The observed impedance spectra indicated that the magnitude of grain boundary resistance R-gb becomes more prominent compared to grain resistance R-b at room temperature, and with the increase in T-SM, R-gb decreases faster than the intrinsic R-b. The frequency response of the imaginary part of impedance showed relaxation behavior at every T-SM, and the relaxation frequency variation with T-SM appeared to be of Arrhenius nature and the activation energy has been estimated to be 0.37 eV. A complex modulus spectrum was used to understand the mechanism of the electrical transport process, which indicated that a non-Debye type of conductivity relaxation characterizes this material.