Application of micromagnetics to a boundless plate

The case of magnetization reversal in a boundless plate of magnetically homogeneous material is treated in the framework of micromagnetics. It is assumed that the magnetocrystalline symmetry axis and the applied field lie along the normal of the plate surface. The mathematical analysis performed facilitates the determination of the nucleation field in an exact analytical way, leading to the conclusion that nucleation takes place by spin rotation in unison. Some indirect experimental evidences are discussed.