Electrical and magnetic properties of coprecipited ba-hexaferrites with addition of SiO2

Preliminary results on the effects of magnetic, electrical and structural characteristics of BaFeOig, with addition of SiO:, prepared by the chemical coprecipitation method are reported. Several firing temperatures were used to investigate the admixture of SiU2 in the samples. Experimental data of electrical conductivity were obtained by ac measurements. Results are presented in terms of thermal and frequency dependent conductivity, a(a>). Universal a(0)%2bAaG-iype behavior is observed for loga(co) vs logf, while loga((o) against JOOO/T, at fixed frequencies, exhibit deviation of an Arrhenius behavior as frequency increases. Generally speaking, curves of ac measurements follow the jump relaxation model. The addition of SiU2 modifies slightly the observed conductivity. Saturation magnetization and coercitivity as a function of the thermal treatment of the samples, in the interval 950°C-1220°C, are also reported. © 1999 Trans Tech Publications,.

VIVO