Influence of addition of copper cadmium ferrite on the dielectric and electrical behavior of BaSrTiO3 ceramics

Polycrystalline composites of (1 − x) (Ba0.7Sr0.3TiO3)–x(Cu0.5Cd0.5Fe2O4) (x = 0.15, 0.30, 0.45) were prepared by a modified wet chemical method. X-ray diffraction studies at room temperature confirmed the formation of polycrystalline composite with perovskite–spinel structure. Scanning electron micrographs also suggest polycrystalline microstructure with the grains of unequal size distributed throughout the pellet samples. Dielectric studies of the composites reveal that the effect of ferrite in the composites is to shift the ferroelectric–non-ferroelectric phase transition to higher temperature side. Complex impedance spectroscopy analysis indicated negative temperature coefficient of resistance behavior identical to semiconductors. The activation energy calculated from the temperature dependence of conductivity pattern shows that the conduction process can occur due to the hopping of electrons between Fe3+ and Fe2+, leading to the contribution of both single and doubly-ionized oxygen vacancies.