title: Three-dimensional observation of magnetic vortex cores in stacked ferromagnetic discs.
abstract: Electron holographic vector field electron tomography visualized three-dimensional (3D) magnetic vortices in stacked ferromagnetic discs in a nanoscale pillar. A special holder with two sample rotation axes, both without missing wedges, was used to reduce artifacts in the reconstructed 3D magnetic vectors. A 1 MV holography electron microscope was used to precisely measure the magnetic phase shifts. Comparison of the observed 3D magnetic field vector distributions in the magnetic vortex cores with the results of micromagnetic simulations based on the Landau-Lifshitz-Gilbert equation showed that the proposed technique is well suited for direct 3D visualization of the spin configurations in magnetic materials and spintronics devices.
authors.affiliation: Central Research Laboratory, Hitachi, Ltd. , Hatoyama, Saitama 350-0395, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanigaki
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Shimakura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Akashi
authors.forename: Ruriko
authors.initials: R
authors.lastname: Tsuneta
authors.forename: Akira
authors.initials: A
authors.lastname: Sugawara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shindo
keywords: Magnetic vortex; electron holography; ferromagnetic disc; vector field tomography