High-frequency dielectric behaviour of Li-Mg ferrites

Dielectric properties such as dielectric constant (epsilon') and dielectric loss tangent (tandelta) of mixed Li-Mg ferrites have been measured at room temperature in the frequency range 1 to 13 MHz using an HP 4192A impedance analyser. Plots of dielectric constant (epsilon') vs. frequency show a normal dielectric behaviour of spinel ferrites. The frequency dependence of dielectric loss tangent (tandelta) is found to be abnormal, giving a peak at certain frequency for all mixed Li-Mg ferrites. A qualitative explanation is given for the composition and frequency dependence of the, dielectric constant and dielectric loss tangent. (C) 2003 Elsevier Science B.V. All rights reserved.