The conduction mechanism of Cu-Si ferrite

The mixed ferrite Cu1+x Six Fe2−2x O4; with 0 ≤ x ≤ 0.3 in step of 0.05 were prepared by standard ceramic techniques. The X-ray analysis confirmed that the compositions are well formed in a single phase. The d.c. and a.c. electrical conductivity as a function of temperature have been studied. The relation ln σ vs. T−1 showed two regions with different slopes for all values of x except x = 0.0 showed one slope only. The two activation energies around a kink point called Tk were calculated. The change of the slope at Tk was attributed to a change in the nature of type of conduction mechanism (i.e. from n-type to p-type). The activation energies were greater than 0.3 eV; which clearly suggested that the conduction is due to small polaron model.