A STUDY ON SUBSTITUTION ELEMENTS FOR BARIUM FERRITE PARTICLES FOR PERPENDICULAR MAGNETIC RECORDING

Abstract

  Ba ferrite particles with CO²⁺-M (M = Ti⁴⁺, Sn⁴⁺, Ge⁴⁺, Nb⁵⁺, Sb⁵⁺, V⁵⁺, W⁶⁺, Mo⁶⁺) and Zn²⁺-Nb⁵⁺ substitutions have been studied from the viewpoint of use for perpendicular magnetic recording. It was found that the Co-Ti, Co-Nb and Co-Sb particles are usable, because they provide controllable coercivity below 1000 Oe, large saturation magnetization, small particle size below 0.1μm and sharp particle size distribution, that are all required for this purpose. Among them, the Co-Ti particles show the highest saturation magnetization. Furthermore, Sn ions were found to be an attractive element which can reduce the temperature dependence of coercivity for Ba ferrite particles, without significant reduction in the Curie temperature.