Magnetization Curves for Polycrystalline Ferromagnetics

Abstract

Recently described developments have led to greatly improved agreement between theory and experiment for the magnetization curves of single crystals of iron and iron-silicon in the region where magnetization proceeds by rotation of domain vectors against the action of magnetocrystalline forces, i.e. in the range 10-500 oersteds. On the basis of the assumption that in polycrystalline material the magnetization is approximately uniform from grain to grain, which is rendered plausible by consideration of internal demagnetizing effects, a method is developed for deriving the magnetization curves of such material by averaging the fields required to produce a given magnetization in the different constituent grains, rather than by averaging the magnetizations produced in the different grains by a given field. The application of this method to specimens with known distributions of grain orientations is shown to give results in fair agreement with experiment.