DIELECTRIC BEHAVIOR OF LITHIUM CADMIUM FERRITES

The dielectric constant (epsilon') and dielectric loss tangent (tan-delta) of mixed Li-Cd ferrites of various compositions are measured at room temperature in the frequency range 1 to 100 kHz using a capacitance bridge. Plots of dielectric constant (epsilon') versus frequency show a normal dielectric behaviour of spinel ferrites. The frequency dependence of dielectric loss tangent (tan-delta) is found to be abnormal, giving a peak at a certain frequency for all the samples of Li-Cd ferrites. However, Li0.3Cd0.4Fe2.3O4 does not show a peak in the frequency range 1 to 100 kHz. A qualitative explanation is given for the composition and frequency dependence of the dielectric constant and dielectric loss tangent. The dielectric constant for these mixed ferrites is approximately inversely proportional to the square root of the resistivity.