THE INFLUENCE OF SPIN-REORIENTATION ON THE DIELECTRIC BEHAVIOR OF COBALT-SUBSTITUTED W-TYPE BARIUM-ZINC HEXAGONAL FERRITES

Dielectric measurements of cobalt substituted W-type barium-zinc hexag onal ferrites are undertaken both as a function of frequency and tempe rature. The dielectric constant is found to decrease continuously with increasing frequency while it increases continuously with increasing temperature. The variation of dielectric constant with dopants concent ration is explained on the basis of magnetic cation orientation. From the temperature variation of dielectric constant two transitions, one due to the spin reorientation in the temperature range 450-500 K and t he other one due to a ferri to paramagnetic transition have been obser ved. Suitable explanations for the observed behavior are given.