What is a domain wall?

The term domain wall originates from the science of solid state physics and describes an interface between two magnetic domains in a material. Domains are region-like areas in a ferromagnetic material in which the magnetic moments of the atoms or molecules are aligned in a certain direction.

How is a domain wall formed?

In a ferromagnetic material, the magnetic moments of the atoms or molecules are normally oriented in random directions, resulting in an overall magnetic field of zero. However, the application of an external magnetic field or other magnetic interactions can create domains in which the magnetic moments are oriented in the same direction. These domains have different magnetic orientations and sizes.

Domain walls are formed at the boundaries between neighboring domains and can take different shapes depending on the properties of the material and the interactions between magnetic moments. There are different types of domain walls, including Bloch walls, Néel walls and other complex structures.

What is the function of domain walls?

The domain wall forms a transition region where the magnetic moments gradually change from one domain to another. Within the domain wall, the magnetic moments can orient themselves in different directions, resulting in a lower overall magnetic field. Domain walls can move and change position when an external magnetic field is applied or other magnetic forces act.

Where do domain walls have practical applications?

Domain walls play an important role in magnetism research and technology. They affect the magnetic properties of materials and can, for example, influence magnetization reversal or magnetic responses to external influences. The movement of domain walls can also lead to magnetic phenomena such as magnetoresistance or magnetic anisotropy.

In magnetic data storage, such as hard drives, domain walls are deliberately manipulated to store and retrieve information. Through the application of external magnetic fields, domain walls can be shifted or reversed in polarity to represent magnetic ones and zeros used to store data.