La-Co共置換M型Srフェライトの酸素分圧制御によるCo濃度増加及び単相化に関する研究

Abstract

The La-Co cosubstituted M-type strontium ferrite attracts attention as a base material for high-performance ferrite magnets. It is known that the uniaxial magnetic anisotropy of the material is enhanced by increasing the amount of Co by heat treatment under high oxygen pressure, but there is a problem in obtaining a pure sample. The present study investigated the conditions to obtain a single phase with increased La-Co substitution by heat treatments under several oxygen pressures. A single phase of M-type ferrite was obtained up to x = 0.35 at pO₂ = 1 atm, and up to x = 0.65 at pO₂ = 10 atm with the composition formula of Sr₁-xLaxFe₁₂-xCoxO₁₉. The magnetic anisotropy is enhanced according to the Co concentration in these samples.