title: Direct observation and dynamics of spontaneous skyrmion-like magnetic domains in a ferromagnet.
abstract: The structure and dynamics of submicrometre magnetic domains are the main factors determining the physical properties of magnetic materials. Here, we report the first observation of skyrmion-like magnetic nanodomains in a ferromagnetic manganite, La0.5Ba0.5MnO3, using Lorentz transmission electron microscopy (LTEM). The skyrmion-like magnetic domains appear as clusters above the Curie temperature. We found that the repeated reversal of magnetic chirality is caused by thermal fluctuation. The closely spaced clusters exhibit dynamic coupling, and the repeated magnetization reversal becomes fully synchronized with the same chirality. Quantitative analysis of such dynamics was performed by LTEM to directly determine the barrier energy for the magnetization reversal of skyrmion-like nanometre domains. This study is expected to pave the way for further investigation of the unresolved nature and dynamics of magnetic vortex-like nanodomains.
authors.affiliation: Electron Microscopy Group, Surface Physics and Structure Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan. m.nagao@aoni.waseda.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nagao
authors.forename: Yeong-Gi
authors.initials: YG
authors.lastname: So
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Masaaki
authors.initials: M
authors.lastname: Isobe
authors.forename: Toru
authors.initials: T
authors.lastname: Hara
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ishizuka
authors.forename: Koji
authors.initials: K
authors.lastname: Kimoto