JMS_V2_N2_RP5 Taminder Singh Arun Katoch Iqbal Singh Journal on Material Science 2347–615X 2 2 18 22 Hexagonal Ferrites, X-ray Diffraction, Scanning Electron Microscope, Thermoelectric Power, AC Conductivity The Seebeck Coefficient for the strontium ferrites Sr_1-x RE_x Fe₁₂ O₁₉ (where RE = Dy, x = 0.0, 0.10, 0.20 and 0.30), which have been prepared by employing the ceramic technique, were studied in the temperature range 313-473K. The value of thermoelectric power seems to increase with increasing temperature where as the AC conductivity has been observed to be independent of frequency at high temperatures for all values of x. In the relatively low temperature region, thermoelectric power value has been found to be negative confirming that the majority of carriers are electrons thereby indicating the rare earth substituted strontium ferrites to be classified as n-type semiconductors. The X-ray diffraction patterns show that the prepared samples have a single phase. The lattice parameters 'c' and 'a' were found to decrease whereas the X-ray density increases with increasing RE content. It has been found that the value of electrical conductivity also increases with an increase in RE content. The dispersion of dielectric constant has been discussed in the light of Koops model and hopping conduction mechanism. July – September 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2817