Field evolution of multivortex and cross-tie states in Permalloy thin films

[[abstract]]Field evolution of vortex and cross-tie states is investigated by magnetic force microscopy imaging experimentally. We found that the vortices move perpendicular to the field direction. For the multivortex states, as the external field is perpendicular to the magnetization direction of the rhombic domain, which is enclosed by two neighboring vortices, the rhombic domain tilts. When the external field is parallel/antiparallel to the magnetization direction of the rhombic domain, this domain is extended/contracted. For the cross-tie state, the vortex and antivortex cores annihilate pair by pair in series when the field is applied along the short axis. When the magnetic field is applied along the long axis, the Bloch line moves along the short-axis direction till it, as a whole, annihilates near the edge of the elliptical thin film.[[fileno]]2020236010017[[department]]動機