J. Phys. III France
Volume 7, Numéro 4, April 1997
Page(s) 883 - 894
DOI: 10.1051/jp3:1997163
J. Phys. III France 7 (1997) 883-894

Dielectric Behavior in BaCO 2xFe\boldmath 12-2xO 19

A.M. Abo El Ata and M.A. El Hiti

Physics Department, Faculty of Science, Tanta University, Tanta, Egypt

(Received 30 July 1996, revised 9 December 1996, accepted 6 January 1997)

The real dielectric constant $\epsilon{'}$ and loss factor tan $\delta$ were studied as function of frequency f, temperature T and composition x for a series of samples of BaC $_{{\rm o}2x}$Zn xFe 12-2xO 19 hexagonal ferrite system with x = 0.4, 0.8, 1.2, 1.6 and 2 prepared using the usual ceramic technique. The experimental results indicated that $\epsilon{'}$ and tan $\delta$ decrease as the frequency increases and temperature decreases. The studied samples showed abnormal dielectric behavior (or relaxation peaks) which were shifted towards higher frequency as the temperature and substitution of Co and Zn ions increase. Increasing the Co and Zn ions substitution for $x \leq 1.2$, $\epsilon{'}$ and tan $\delta$ decrease reaching minima while activation energy for dielectric relaxation $E_{\rm D}$ and pre-exponential constant f0 increase reaching maxima at x = 1.2. The behavior was reversed for x > 1.2, where $\epsilon{'}$ and tan $\delta$ increase while $E_{\rm D}$ and f0 decrease.

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