An investigation of anisotropy of cobalt-surface-modified iron oxide magnetic particles

Surface treatment experiments on nonstoichiometric iron oxide are described, along with a theoretical analysis which suggests that the uniaxial anisotropy of cobalt-surface-modified iron oxide particles is not induced by the magnetic field of the inner core of iron oxides, but rather is due to the shape anisotropy being larger than the magnetocrystalline anisotropy of imperfectly crystallized CoFe₂ O₄. It is concluded that the crystalline imperfection of CoFe₂O₄ on the outer layer of iron oxides particles decreases the magnetocrystalline anisotropy and limits the enhancement rate of the coercivity of cobalt-surface-treated iron oxide particles