FREQUENCY AND COMPOSITION DEPENDENCE OF DIELECTRIC BEHAVIOR OF MIXED LI-CD FERRITES

The dielectric constant (epsilon') and dielectric loss tangent (tan de lta) of mixed Li-Cd ferrites of different compositions sintered at 130 0-degrees-C have been measured at room temperature in the frequency ra nge 1-100 kHz using a capacitance bridge. Plots of dielectric constant (epsilon') versus frequency show a normal dielectric behaviour of spi nel 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 in the case of Li0.3Cd0 .4Fe2.3O4 does not show a peak in the frequency range 1-100 kHz. A qua litative explanation is given for the composition and frequency depend ence of the dielectric constant and dielectric loss tangent. The diele ctric constant for these mixed ferrites is approximately inversely pro portional to the square root of the resistivity. Plots of dielectric c onstant (epsilon') versus cadmium content is approximately an inverse image of that of resistivity versus cadmium content.