Magnetic and Electrical Properties of Bi₂O₃ Modified BaFe₁₂O₁₉ Hexagonal Ferrite

Abstract

The Ba-hexagonal ferrites (BaFe 12 O 19 ) with Bi 2 O 3 as a sintering aid have been studied. The beneficial effects on magnetic and electrical properties are obtained for a ∼2.5 mol% Bi 2 O 3 content. The Bi 3+ ions in the present system seem to substitute for Fe 3+ at octahedral sites leading to formation of BaFe 12- x Bi x O 19 ( x <0.32) type ferrite. It leads ∼12.4% decrease of the saturation magnetization and an increase of T c from 457 to 480°C in comparison to pure Ba-ferrite. Coercivity ( H c ) is found to decrease on Bi 2 O 3 addition and sintering the samples at higher temperatures (1100–1300°C) for prolonged periods. The bulk density, compressive strength and electrical (AC) resistivity are measured for all the useful samples. The results considered together successfully account for the effects of Bi 2 O 3 on the growth of Ba-ferrite particles.