Some of the Magnetic Properties of Polycrystalline Soft Ferrites : Origins and Developments of a Model for the Description of the Quasistatic Magnetization

Abstract
Since the first laws discovered by Lord Rayleigh in 1887, the literature has given a spectacular number of works in the magnetisation modeling field. The authors remark that most of these works are devoted to soft magnetic metals with intent to improve the knowledge of the dynamic power losses (anomalous losses), and that only a few models have really been developed on true physical considerations. In the soft ferrites area, Globus has proposed a model of magnetisation based on the motions (reversible bulgings and irreversible movements of translation) of a single 180° domain wall contained in an ideal spherical grain. The authors discuss the main assumptions of this model with regard to their own practical experience of soft ferrites (actions of external anisotropies), and also to some particular results published by other workers. In the last part of this paper, a new progress on the Globus model is presented which concerns the hysteresis simulation. The result is tested on actual hysteresis loops of different shapes.