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In this paper a phenomenological approach, based on a generalization in two dimensions of the classical scalar Preisach model, is exploited and identified to reproduce the magnetization curves obtained by accurate micromagnetic simulations of both isotropic and anisotropic polycrystalline Fe–Si films with different values of the anisotropy constants. The identification problem is realized using a suitable set of analytical equations and performing a best fit procedure to the data obtained from micromagnetic simulations of both scalar and rotational loops. The correct reconstruction of all the magnetization processes, as well as of the associated magnetic losses, is achieved through the choice of a small number of either circular or elliptical hysterons, as well as by the implementation of a simple “moving technique” that is necessary to take into account the non-collinearity between the field and the magnetization that occurs in presence of a global uniaxial anisotropy. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the analysis of multi-domain nanostructures is made by means of numerical approaches. The Landau–Lifshitz–Gilbert LLG equation is used to compute the magnetic hysteresis loops for different alternate scalar polarizations. The data computed are then used to identify the parameters of a phenomenological model, based on the extension of the Preisach model in 2-D. The identification in this case is the evaluation of the size and the position of the hysterons in the H-plane. Each hysteron is associated to a domain of the nanostructure and the assembly of hysterons reproduces with satisfactory accuracy the hysteretic behavior of the nanostructure computed by the LLG equation with an extremely reduced computational time. Some possible relationships between the magnetization nanostructure and the parameters of the hysteron are suggested. These relationship should be used for a “blind” prediction of the magnetization state of much larger magnetic structures, whose computation using the LLG equation is not possible in practice due to the enormous computational time, supposing that magnetic structures with the same aspect ratio exhibit a similar distribution of magnetic domains. The theory is applied here to an example of Permalloy nanostructure. [Copyright &y& Elsevier]

In this paper, we discuss the numerical modeling of hysteresis in magnetic steels with oriented and nonoriented grain. The modeling is fully 3-D, but it is applied here to typical 2-D magnetic problems. Starting from a vector generalization of the Preisach model, we introduce here the concept of an operative magnetic field, function of the state of magnetization of the material. This operative field is introduced to reproduce with more accuracy the peculiar behavior of Si-Fe steels approaching the saturation state. The properties of the model are discussed and some examples are reported. [ABSTRACT FROM AUTHOR]

In this paper we discuss about the possibility to reproduce the behavior of a magnetic material at micromagnetic scale with a phenomenological vector model of hysteresis based on the definition of a vector hysteron. We compare data computed by means of two different static magnetic models. The former is based on the solution of Brown's equation (micromagnetic scale). The latter is a vector generalization of the Classical Scalar Preisach Model (macromagnetic scale). We show that the magnetization versus applied field curves computed by both models are in good agreement, and that the macromagnetic-scale model is able to reproduce the physical behavior of the magnetic materials at micromagnetic scale. [ABSTRACT FROM AUTHOR]