Dielectric behaviour in Mg–Zn ferrites

Abstract

The effect of frequency, temperature and composition on the dielectric behaviour was studied for Mg x Zn 1− x Fe 2O 4 ferrite samples prepared using the usual ceramic technique. The experimental results indicated that the dielectric loss tan δ and real dielectric constant ε′ increase as the temperature increases, and as frequency and Mg 2+ ion substitution decrease. Abnormal dielectric behaviour (relaxation peaks) were observed on tan δ curves for all samples at relatively high temperatures. The relaxation frequency f D was found to be shifted to higher values as the temperature increases. ε′ and tan δ decrease whereas the activation energy for dielectric relaxation E D increases as Mg 2+ ion substitution increases. The hopping of localised electrons between Fe 2+ and Fe 3+ ions is responsible for electric conduction and dielectric polarisation in the studied Mg x Zn 1− x Fe 2O 4 ferrites.