Magnetic and Electrical Properties of Bi₂O₃ Modified BaFe₁₂O₁₉ Hexagonal Ferrite

Abstract

The Ba-hexagonal ferrites (BaFe12O19) with Bi2O3 as a sintering aid have been studied. The beneficial effects on magnetic and electrical properties are obtained for a ∼2.5 mol% Bi2O3 content. The Bi3+ ions in the present system seem to substitute for Fe3+ at octahedral sites leading to formation of BaFe12-x Bi x O19 (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 Bi2O3 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 Bi2O3 on the growth of Ba-ferrite particles.

Magnetic and structural properties of M-type barium hexaferrite prepared by co-precipitation

“…The values in Table 1 refer to the intensity of the magnetic field required to reduce the magnetisation of the samples to zero, after the magnetisation of the sample has reached saturation. The results obtained agree well with the published literature of [19,20].…”

Development of magneto-dielectric materials based on Li-ferrite ceramics

“…In the present study, Bi 2 O 3 was used as sintering aid to improve the sintering property of Li 0.50 Fe 2.50 O 4 ceramics. Bi 2 O 3 has been widely used to improve the densification behavior of various ferrites because it forms a liquid phase during sintering process due to its relatively low melting point (∼820 • C) [15][16][17][18]. Although 1% Bi 2 O 3 is sufficient to attain almost fully dense Li 0.50 Fe 2.50 O 4 ceramics, 3% was found to be necessary to maintain sufficiently low dielectric loss tangent (see Part II) [19].…”

Development of magneto-dielectric materials based on Li-ferrite ceramics

“…Fabrication of the Bi 2 O 3 -doped samples is a multi-step process. Firstly, a liquid phase was formed during heating of the pellets above the melting point of Bi 2 O 3 (∼820 • C) [21][22][23][24]. If any low melting eutectics were formed between Bi 2 O 3 and other components, the liquid phase formation temperature can be lower than 820 • C. The liquid layer surrounded and wetted grains by filling at grain boundaries.…”