AC conductivity of Li-Ge ferrite

The alternating current conductivity of Li_0.5+0.5xGe_xFe₂O₄ (where x=0.0, 0.2, 0.3 and 0.5) has been studied as a function of frequency, whereby the conductivity showed a dispersion with respect to frequency. In the range of dispersion it was found that sigma ( omega ) alpha omega ^S, where S is a constant. At f=10⁵ Hz, S is equal 0.45, 0.8, 0.7 and 0.6 for x=0.0, 0.2, 0.3 and 0.5 respectively. The variation of loss tangent (tan delta ) with frequency was studied in the range from 100 Hz to 1 MHz. There were peaks in tan S at f=5.5*10⁴, 5*10⁴ and 1.5*10⁵ Hz for the samples of x=0.2, 0.3 and 0.5 respectively. However, for x=0.0, tan delta gave a maximum in the range of frequency (2-6)*10⁴ Hz. At the same time, a minimum value of epsilon ' (the real part of the complex dielectric) was found at the corresponding frequency value.