ABSTRACT
The magnetization process can be understood from the consideration of the evolution of the domain state of the sample as a magnetic field is applied. This can be rather complex and will implicitly depend on the energy considerations of the particular sample in question. Magnetic anisotropy, whether in the form of magnetocrystalline anisotropy or shape anisotropy, will define the orientation of the magnetization vector within the ferromagnet. People usually define an easy axis, or more correctly, a direction of easy magnetization and a hard axis. In between the magnetic domains, the magnetic moments must rotate from one orientation to the next, in accordance with the orientation of the magnetic domains. This will mean that there will be components of the magnetization, within the domain walls, that lie along hard axes, and hence will increase the magnetic energy. Since the lower energy configuration will be that in which the magnetization lies along an easy axis.
