Fine spinel-type ferrimagnetic particles containing Fe-Co-Ni and process for producing the same

摘要

Fine spinel-type ferrimagnetic particles of the present invention have a composition represented by the formula (I): (CoO)x(NiO)y•n/2Fe2O3 wherein 2.0 < n=Fe/(Co + Ni) < 3.0, 0.4 ≤ x ≤ 0.9, 0.1 ≤ y ≤ 0.6 and x + y = 1. The fine spinel-type ferrimagnetic particles exhibit a high coercive force in spite of fine particles.