Dynamic study of domain wall in a patterned permalloy submicron wires

In summary, we have successfully demonstrated the domain wall motion along the direction of perimeter of a ferromagnetic ring at onion state. As the results of the MR measurement with rotating the ring at different constant fields, the critical field to form onion state is near 200 Oe and the lowest field which can still drag the domain wall is between 100 and 50 Oe.