Comment on 'Giant Skyrmions Stabilized by Dipole- Dipole Interactions in Thin Ferromagnetic Films'

摘要

In a recent Letter [1], M. Ezawa claims the existence of novel Skyrmion states in magnetic systems stabilized by dipole-dipole interactions. In our Comment, we demonstrate that the results of Ezawa are wrong: the solutions for "giant Skyrmions" presented in Ref. [1] are only a limiting case of well-known solutions for bubble domains [2], while real Skyrmion solutions have been overlooked. The standard micromagnetic model for a thin magnetic layer investigated in [1] includes the exchange stiffness energy (A), intrinsic or/and induced uniaxial anisotropy (K) and Dzyaloshinskii-Moriya (DM) interactions (D), Zeeman (H ? M), and stray-field (wd) energies. Developing and extending the micromagnetic methods applied in Refs.