Magnetic Properties of Bi and Si Oxides-Doped M-Type Barium Ferrite

Abstract

Barium ferrite doped with Bi and Si oxide was sintered densely at a low temperature of approximately 900 °C, suppressing grain growth. This ferrite magnet had a two-phase structure comprising a barium ferrite phase and an amorphous bismuth silicate phase. We investigated the relationship between the magnetic properties and SiO 2 content and found that the coercive force increased in proportion to the SiO 2 content. It was suggested that the coercive force increased because each grain was magnetically shielded by a grain boundary phase.