Domänenwandenergie

Domänenwandenergie refers to the energy associated with the boundary between magnetic domains within a ferromagnetic material. Ferromagnetic materials, such as iron, are composed of small regions called magnetic domains, where the magnetic moments of atoms are aligned in the same direction. These domains are separated by domain walls, which are transitional regions where the magnetization direction gradually changes.

The formation of domain walls is a consequence of minimizing the total magnetic energy of the material. This total energy includes exchange energy, anisotropy energy, magnetostatic energy, and magnetostriction energy. Exchange energy favors parallel alignment of neighboring atomic moments, while anisotropy energy prefers magnetization along specific crystallographic directions. Magnetostatic energy arises from the magnetic field produced by the magnetization itself, and magnetostriction is the change in shape of a material when subjected to a magnetic field.

Within a domain wall, the magnetization direction rotates from the orientation in one domain to that in the adjacent domain. This rotation requires energy, known as the domain wall energy. This energy is primarily composed of exchange energy and anisotropy energy contributions. The width of a domain wall is a balance between these two energies: exchange energy favors a wider wall to reduce the gradient of magnetization, while anisotropy energy favors a narrower wall to minimize the volume where magnetization is not aligned with easy axes.

The presence and movement of domain walls are crucial for understanding magnetic phenomena like hysteresis, magnetization reversal, and the response of magnetic materials to external magnetic fields. The energy associated with domain walls influences magnetic properties such as coercivity and permeability. Manipulating domain wall motion is a key principle in technologies like magnetic data storage.