Magnetization reversal mechanism of the chain of two oblate ellipsoids

Abstract

A model of magnetization reversal for the chain of two oblate ellipsoids is proposed. The magnetization loops, the angular dependencies of coercivity Hc and the critical field H0 were calculated with the considerations of the uniaxial magnetocrystalline anisotropy, the shape anisotropy, as well as the interaction anisotropy of the ellipsoids. The results show that for small anisotropic factor ω(=2K1/M2s), the magnetization reversal of the chain is inclinable to the fanning process, while for the large one, the reversal to parallel rotation process. When the crystalline anisotropy of the ellipsoids was considered, the coercivity of the chain of two oblate ellipsoids was larger than that of Jacobs and Bean’s chain of two spheres by a factor of (1+6ω/π) for fanning process and of (1+2ω/π) for parallel rotation process. When ω equals 0 and the ellipsoids become spheres, the results of the model become those of Jacobs and Bean’s model of chain of two spheres. The results show also that the effect of the crystalline anisotropy on the magnetization reversal of the chain is larger than that of interaction anisotropy. This model could be used to explain the magnetization reversal mechanism of the oriented Ba-ferrite particulate media.