Pressures on cylindrical magnetic domain walls

The pressures on cylindrical magnetic domain walls are discussed with particular emphasis on bubbles, that is, near-circular domains. In the case of anisotropic wall energy, bubbles will be slightly elliptical, and a formula is derived relating the ellipticity to the anisotropic wall energy. Various formulations for the average magnetic field at a domain wall are presented. The problem of cutting bubbles off from a strip wall is investigated. It is seen that the field required to cut off a bubble can be up to 40 percent less than the 4πM
s
required to push two parallel walls together for certain geometries