A Bloch wall is a type of domain wall that forms in magnetic materials. It is a transition region between two regions of the material where the magnetization is oriented in different directions.

In a magnetic material, the atoms have an inherent magnetic moment, which can align with an external magnetic field. When a magnetic field is applied to a ferromagnetic material, the magnetic moments of the atoms tend to align in the direction of the field, creating a magnetic domain with a uniform magnetization. A Bloch wall forms at the boundary between two such domains, where the direction of magnetization gradually changes from one domain to the other.

The magnetization in a Bloch wall rotates continuously within the wall, rather than abruptly changing direction. The direction of magnetization at any point within the wall can be described by a Bloch vector, which varies smoothly across the wall.

The width of a Bloch wall depends on the properties of the material and the strength of the magnetic field. In some materials, the width of the wall can be as small as a few nanometers, while in others it can be several micrometers or more.

The formation and behavior of Bloch walls are important in the study of magnetic materials and have many practical applications. For example, they play a crucial role in the operation of magnetic memories and in the development of magnetic sensors and spintronic devices. Read more about  Bloch function