The conduction mechanism of Cu-Ge ferrite

The electric conductivity, a (DC and AC), drift mobility and dielectric properties of germanium-substituted copper ferrite, with the chemical formula Cu(1+x)Ge(x)Fe(2-2x)O(4) (where x = 0.0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3), have been studied. Plots of In sigma T versus 10(4)/T (K) are linear and showed two sloping regions for all values of x except for the values 0.0 and 0.05, which showed one slope only. The two activation energies around a kink point called T(k) were calculated. The electrical conduction in these ferrites is explained on the basis of the hopping mechanism. The values of the charge carrier mobility have been calculated from the experimental values of electrical conductivity which increased exponentially with increasing temperature. Dielectric properties such as dielectric loss tangent tan (5 were measured at elevated temperature in the frequency range from 10(2) to 10(6) Hz. The variation of these parameters with temperature is explained qualitatively. An attempt is made to explain the possible mechanism. (C) 2010 Elsevier Ltd. All rights reserved.