Orientation and internal structure of domain walls in ferromagnetic films with anisotropic Dzyaloshinskii-Moriya interaction

Abstract We present an analytical study of domain-wall internal structure and orientation in a ferromagnetic film with out-of-plane anisotropy and the anisotropic interfacial Dzyaloshinskii-Moriya interaction (iDMI). The term “anisotropic” means that the iDMI constant is different for different in-plane directions. The interplay between the magnetostatic interaction and the iDMI in a domain wall defines both its structure and orientation. In the case of the isotropic iDMI there is no preferable orientation of the DW in the film plane leading to formation of labyrinth domain structure with random shapes of the domains. In the case of the anisotropic iDMI an oriented domain stripe structure and zigzag domains appear. Depending on system parameters, either the Bloch domain walls, or the Neel ones or the hybrid canted walls realize in the magnetic film. The spatial orientation of the DW and the orientation of the magnetization rotation plane in the DW are intimately related by a simple linear ratio. The analytical results are corroborated by micromagnetic simulations.