DIELECTRIC BEHAVIOR IN BACO2XZNXFE12-2XO19

The real dielectric constant epsilon' and loss factor tan delta were s tudied as function of frequency f, temperature T and composition x for a series of samples of BaCo2x ZnxFe12-2xO19 hexagonal ferrite system with x = 0.4, 0.8, 1.2, 1.6 and 2 prepared using the usual ceramic tec hnique. The experimental results indicated that epsilon' and tan delta decrease as the frequency increases and temperature decreases. The st udied samples showed abnormal dielectric behavior (or relaxation peaks ) which were shifted towards higher frequency as the temperature and s ubstitution of Co and Zn ions increase. Increasing the Co and Zn ions substitution for x I 1.2, epsilon' and tan delta decrease reaching min ima while activation energy for dielectric relaxation ED and pre-expon ential constant f(0) increase reaching maxima at x = 1.2. The behavior was reversed for x > 1.2, where epsilon' and tan delta increase while E-D and f(0) decrease.