Some recent developments in uniaxial ferromagnets

A brief outline is given of the most recent advances in the field of high uniaxial anisotropy materials of technological importance. The survey is limited to rare earth-3d transition metal compounds of the type RCo
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(R, rare earth) and hexaferrites. As to the problem of phenomenology of magnetic anisotropy, some recent developments will be summarized: The first order magnetization processes (FOMP) in dependence on the first three anisotropy constants; The use of the singular point detection techniques (SPD) both for anisotropy fields measurements and for the study of FOMP; The model of two canted sublattices having high competing anisotropy. A connection exists between the observed high order constants, that justify the existence of FOMP, and the canting of sublattices: the latter phenomenon is responsible for a distortion of the anisotropy energy surface and leads to effective constants of high order.