ABSTRACT
This chapter investigates the local magnetic properties in the vicinity of domain boundaries. These regions are called domain walls and have properties that are very different from the rest of the domain. We may define the domain-wall energy as the difference in energy of the magnetic moments when they are part of the domain wall and when they are within the main body of the domain. The interaction energy, also known as the exchange energy, tends to make the walls thicker because this energy in a ferromagnet is minimized when neighboring moments are aligned parallel. The anisotropy energy tends to make the domain wall thinner because anisotropy energy is lowest with all moments aligned along crystallographically equivalent axes known as the “easy” axes. Closure domains occur more often in cubic materials than in hexagonal materials because the cubic anisotropy ensures that the directions at right angles to the magnetization in a given domain are also magnetically easy axes.
