Abstract
A series of polycrystalline Y-type hexaferrites with composition Ba2Ni2-xZnxFe12O22 (where 0.0 less than or equal to x less than or equal to 2.0) were prepared by the standard ceramic method to study the effect of the frequency, temperature and composition on their AC electrical conductivity sigma'(AC), and dielectric properties. It was found that, the AC conductivity shows dispersion at high frequencies. This dispersion was attributed to the interfacial polarization arising from the inhomogeneous structure of the material. At low frequencies the dielectric constant, epsilon', is abnormally high and decreases rapidly with increasing frequency. Dielectric relaxation peaks were observed on the tan delta(F) curves. The results of the dielectric constant and dielectric loss were explained on the basis of the assumption that the mechanism of dielectric polarization is similar to that of the conduction process. (C) 2002 Published by Elsevier Science B.V.