Influence of Mo6+ on Dielectric properties of Copper Ferrites

Two series of copper ferrites are prepared using the chemical compositional formula Cu 1.0-3y Fe 2.0-2xMo x + yO4.0. They are calcinated at 750 C and sintered at 950C. When x =y = 0.0, the ε′ of the basic copper ferrite is probably due to electronic exchange interactions of copper and iron ions as Cu2+ ↔ Cu1+ and Fe3+ ↔ Fe2+. The observed value of dielectric constant (є′) decreases as a function of substituent concentration (x) up to x = 0.20 and for further values of ‘x' it found to increase. In the case of ‘C' (x = 0) series ferrites є′ decreases with substituent concentration (y) up to y = 0.04, later it found to increase. The dispersion of ac resistivity with frequency is observed indicating their strong dependence on frequency as in the case of dielectric behaviour. These results are explained with different possible mechanisms.