STUDY ON EASY MAGNETIZATION AXIS OF ACICULAR BARIUM FERRITE PARTICLES

Abstract

  We have succeeded in the industrial production of acicular Ba ferrite particles with a range of coercivity values (Hc) and high saturation magnetization values (σs), using the topotactic reaction between acicular FeOOH particles and fine BaCO₃ particles. Appropriate baking temperatures and baking times were an important factor in obtaining acicular Ba ferrite particles with a high saturation magnetization value while preventing fusion between these particles. Through SEM and TEM observations of magnetically oriented sheets obtained through trial manufacture, it was verified that the axis of easy magnetization of acicular Ba ferrite particles is perpendicular to the acicular direction. Also, torque curve measurements were used to verify that the magnetically oriented sheets had uniaxial anisotropy. The results show that these properties are suitable for perpendicular magnetic recording media.