Micromagnetic simulation of wall transition structures with self-induced helical anisotropy and their pinning effects

A three-dimensional micromagnetic simulation has been performed to clarify the effect of self-induced anisotropy on domain wall behaviours, such as wall broadening and wall pinning, with wall transitions. Simulation results of the broadening of the domain wall with the transitions agree qualitatively with the Kerr microscope observation: for the wall transition which has a Bloch line between two C-shaped walls without a cap switch at each surface, the broadening of each Neel cap mainly occurs toward the opposite directions and the jog along the wall also becomes larger; for the wall transition which has a cap switch with a Bloch line, Neel caps still keep the same position after broadening. Details of pinning characteristics of the domain walls with the wall transitions by the self-induced helical anisotropy will also be presented.