Dielectric behaviour of mixed Mg-Zn ferrites at low frequencies

The dielectric constant (epsilon'), dielectric loss tangent (tan delta) and complex dielectric constant (epsilon ") of mixed Mg-Zn ferrites of various compositions have been studied in the frequency range of 1-100 Id-It using a capacitance bridge. Plots of dielectric constant vs. frequency show a no rmal dielectric behaviour of spinel ferrites. The frequency dependence of a dielectric loss tangent (tan delta) is found to be abnormal, giving a peak at a certain frequency for all the compositions. A qualitative explanation is given for the dielectric behaviour of Mg-Zn ferrites. The dielectric co nstant for these mixed ferrites is approximately inversely proportional to the square root of the resistivity, The observed results can be explained o n the basis of an electron exchange between Fe2+ and Fe3+ ions. (C) 1999 El sevier Science B.V. All rights reserved.