In order to explain the magnetic annealing effect in ferrites, we have extended our theory of the ferromagnetic uniaxial anisotropy induced by magnetic annealing in metallic cubic solid solutions to cases of ferrites and derived a general expression for the uniaxial anisotropy induced in ferrites. It is shown that our theory of the magnetic annealing effect in ferrites can explain almost all of the available experimental results on the induced uniaxial anisotropy as dependent on the concentration, on the orientation of the magnetic field during annealing, and on the temperature of magnetic anneal. Thus, we conclude that the uniaxial anisotropy induced by magnetic annealing in ferrite is caused by an anisotropic distribution among cations and cation vacancies, namely, by a mechanism similar to that in ferromagnetic metallic solid solutions. In connection with the present study, a criticism has been made on the explanation of the effect proposed recently by Williams et al., and the concentration dependence of the magnetocrystalline anisotropy constant in binary ferrites composed of cobalt ferrite and other inverse ferrite has also been discussed briefly, based on the model given by Van Vleck and extended by Sugihara
