抄録
The magnetic vortex in a ferromagnetic disk has a unique feature of spin configuration to eliminate magnetostatic energy with a vertical bistable magnetization characteristics. We have observed magnetic vortex states in permalloy thin film disks with diameters ranging from 2μm to 25μm, using spin-polarized scanning electron microscopy (SP-SEM). Magnetic vortex states exist throughout range of diameters. At diameters larger than 15μm, multidomain states were also observed, however, a magnetic vortex state should be expected as one of the low-energy states even in a ferromagnetic disk as large as 25μm.
