Spectral, Electrical, Thermoelectrical and Dielectric Properties of (Zn,Zr) Co-doped CuFe<bold>2</bold>O<bold>4</bold>

The effects of Zr+4 and Zn+2 substitution on the electrical, dielectric and spectral properties of non-stoichiometric Cu1-xZnxZryFe2-yO4 + and stoichiometric Cu1-xZnx + yZryFe2 - 2yO4 ferrites prepared by double sintering ceramic technique have been investigated. IR absorption spectra confirm the formation of spinel structure. On the other hand, IR spectra can give an idea about the change of molecular structure of ferrites system due to the perturbation that occurred in Fe3+-O2- bond by introducing Zn and Zr elements. The phase identification of nonstoichiometric (ns) and stoichiometric (s) samples was confirmed by the presence of endothermic peak from DTA curves at around 936 C-degrees in agreement with X-ray diffraction and IR results. The calculated low values of activation energies for conduction are in the range that suggests the conduction is due to thermally activated mobility and the presence of hopping conduction mechanism. Thermoelectric power exhibits positive sign for most s and ns samples. The concentration of charge carrier is constant in the ferromagnetic region. It is also noted that the dielectric constant decreases with increasing Zn and Zr contents. From the above discussion the samples containing Zn and Zr elements have lower B-pp values with low energy loss. From the ESR analysis it can be confirmed that the addition of Zn and Zr generally decrease the power loss which is very important in the application for the manufacturing of a material which is used as a core of transformer at the microwave frequencies.