Effect of LiCl doping on dielectric behavior of copper-zinc ferrite system

Polycrystalline soft ferrite samples were prepared with chemical formula, ZnxCu1-xFe2O4 (x=0.30,0.50,0.70,0.80 and 0.90) doped with controlled amount of lithium chloride (LiCl) by standard ceramic technique. The samples were characterized by XRD, IR absorption techniques. X-ray diffraction studies of the compositions reveal formation of single-phase cubic structure. The values of lattice constant decrease as doping percentage of LiCl is increased from 0.01% to 0.10%. The presence of chlorine ions is confirmed by IR absorption peak in spectrum near 650 cm-1 for all the samples. The investigation on dielectric constant (ε'), dielectric loss tangent (tan δ) and AC resistivity (ρAC) was carried out in the applied field frequency range 100 Hz-1 MHz, at room temperature. Dielectric constant and loss tangent were found to decrease as the frequency increases. This is attributed to the Maxwell-Wagner polarization. Temperature-dependent DC resistivity was carried out in the temperature range from 300 to 800 K. From the compositional study, it was found that the dielectric constant shows decreasing trend with increasing both zinc concentration as well as doping percentage of lithium chloride. Conduction mechanism in these ferrites is discussed on the basis of electron exchange between Fe2+ and Fe3+ ions on the octahedral B-sites