A General Analytical Expression for the Hysteresis Loop Description in Polycrystalline Soft Ferrites

Abstract
The initial form of the Globus model gives a good approach of the description of the macroscopic magnetic properties in polycrytalline soft ferrites by examining the motion of a flat 180° domain wall inside a spherical grain. By the use of a new analytical expression of the magnetization curve calculated using this model, this work studies the effects of the grain shape on the theoretical curves of magnetization. We propose to take the grain outline as a new parameter for introducing a notion of magnetic hardness in the magnetization process. As an example, an experimental comparison between modelled and actual hysteresis loops is shown on polycrystalline YIG sample.