Dielectric behaviour in Ni-Zn ferrites

The dielectric properties were studied as a function of temperature, frequency and composition for a series of Ni1-xZnxFe2O4 ferrite samples prepared by the usual ceramic technique. The real dielectric constant epsilon' and dielectric loss factor tan delta were found to decrease as the frequency increases. Each of epsilon' and tan delta increase on increasing the temperature. Abnormal dielectric behaviour (peaks) were observed for tan delta curves at relatively high temperatures. The relaxation frequency f(D) shifts to higher values on increasing the temperature. Both epsilon' and tan delta increase whereas the activation energy for dielectric relaxation E-D decreases as the Zn2+ ion substitution increases. (C) 1999 Elsevier Science B.V. All rights reserved.