On the Preisach function of ferromagnetic hysteresis

In ferromagnetic materials complex hysteresis curves of magnetization processes can be described by the magnetic history dependent calculation of consecutive Everett integrals of the two-variable Preisach function. For the one-dimensional case, when the external magnetic field varies along a fixed direction, an explicit structure of the Preisach function is proposed offering a better insight into the mechanism of the magnetization process. With the proposed form the rate of change of the magnetization with respect to the applied field depends on the magnetization itself, thus emphasizing the intrinsic nonlinearity of the magnetization curves. Specifically, the magnetization dependence is assumed to be separable as a multiplicative factor, namely, (1−m2). The residual field-dependent part of the Preisach function is assumed to be a bilinear form of a single-variable distribution function which may be interpreted as the probability of the switching of magnetic moments between states of opposite direction, thus representing the coercivity character of the material along the direction of the field. Examples of calculated major and minor hysteresis loops and a method of the determination of the coercivity function from the main experimental hysteresis loop are also given.