A5103024056- Advanced Electron Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Advanced X-ray Imaging Techniques
- Magnetic Properties and Applications
- Force Microscopy Techniques and Applications
- Advanced Condensed Matter Physics
- Integrated Circuits and Semiconductor Failure Analysis
- Advancements in Photolithography Techniques
- Theoretical and Computational Physics
- Characterization and Applications of Magnetic Nanoparticles
- Surface and Thin Film Phenomena
- Geomagnetism and Paleomagnetism Studies
- Advanced Thermodynamics and Statistical Mechanics
- Nonlinear Dynamics and Pattern Formation
- Quantum and electron transport phenomena
- Astro and Planetary Science
- RNA and protein synthesis mechanisms
- stochastic dynamics and bifurcation
- DNA and Nucleic Acid Chemistry
- Non-Destructive Testing Techniques
- Magnetic and transport properties of perovskites and related materials
- Electronic and Structural Properties of Oxides
- High-pressure geophysics and materials
Hitachi (Japan)
2015-2024
Kyushu University
2018-2019
Hitachi (United Kingdom)
2016
Corrected Electron Optical Systems (Germany)
2015
RIKEN Center for Emergent Matter Science
2015
Okinawa Institute of Science and Technology Graduate University
2009-2012
Hitachi High-Tech (Japan)
2006-2010
Japan Science and Technology Agency
2002-2004
A goal in the characterization of supported metal catalysts is to achieve particle-by-particle analysis charge state strongly correlated with catalytic activity. Here, we demonstrate direct identification individual platinum nanoparticles (NPs) on titanium dioxide using ultrahigh sensitivity and precision electron holography. Sophisticated phase-shift for part NPs protruding into vacuum visualized slight potential changes around NPs. The revealed number (only one six electrons) sense...
Topological magnetic (anti)skyrmions are robust string-like objects heralded as potential components in next-generation topological spintronics devices due to their low-energy manipulability via stimuli such fields, heat, and electric/thermal current. While these 2D widely studied, intrinsically 3D electron-spin real-space topology remains less explored despite its prevalence bulky magnets. 2D-imaging studies reveal peculiar vortex-like contrast the core regions of spin textures present...
Electron holography based on two electron biprisms was developed. The upper biprism installed just the image plane of objective lens, and lower one set between crossover point magnifying lens. This system able to control important parameters hologram—fringe space width interference region—independently. enabled us perform interferometry more flexibly. We confirmed good performance did preliminary applications using a 1-MV field-emission microscope.
Electron holographic vector field electron tomography visualized three-dimensional (3D) magnetic vortices in stacked ferromagnetic discs a nanoscale pillar. A special holder with two sample rotation axes, both without missing wedges, was used to reduce artifacts the reconstructed 3D vectors. 1 MV holography microscope precisely measure phase shifts. Comparison of observed distributions vortex cores results micromagnetic simulations based on Landau–Lifshitz–Gilbert equation showed that...
Atomic-resolution electromagnetic field observation is critical to the development of advanced materials and unveiling their fundamental physics. For this purpose, a spherical-aberration corrected 1.2-MV cold field-emission transmission electron microscope has been developed. The following superior properties: stabilized accelerating voltage, minimized electrical mechanical fluctuation, coherent emission. These properties have enabled obtain 43-pm information transfer. On bases these...
Using Lorentz microscopy to directly image vortices, we investigate vortex motion control and rectification in a niobium superconductor. We observe net of vortices along microfabricated channels with spatially asymmetric potential, even though the were driven by an oscillatory field. By observing individual clarify elementary processes involved this rectification. To further demonstrate ability created tiny ``racetrack'' monitor closed circuit channel.
Superconductors can be used as dissipation-free electrical conductors long vortices are pinned. Vortices in high-temperature superconductors, however, behave anomalously, reflecting the anisotropic layered structure, and move readily, thus preventing their practical use. Specifically, a magnetic field tilted toward layer plane, special vortex arrangement (chain-lattice state) is formed. Real-time observation of using high-resolution Lorentz microscopy revealed that images chain begin to...
In order to elucidate the formation mechanism of unconventional arrangements vortices in high- Tc superconducting thin films at an inclined magnetic field layer plane, we investigated structures vortex lines inside by Lorentz microscopy using our 1-MV field-emission electron microscope. Our observation results concluded that are tilted form linear chains YBaCu3O(7,8). Vortex chain-lattice state Bi2Sr2CaCu2O(8+delta), on other hand, all perpendicular and therefore only lined up along Josephson chains.
Nanometre-scale magnetic field distributions in materials such as those at oxide interfaces, thin layers of spintronics devices, and boundaries magnets have become important research targets science applied physics. Electron holography has advantages nanometric observations, the realization aberration correctors improved its spatial resolution. Here we show subnanometre observations inside a sample 0.67-nm resolution achieved by an aberration-corrected 1.2-MV electron microscope with pulse...
We investigate the current-excited magnetization dynamics in a narrow ferromagnetic Permalloy wire by means of Lorentz microscopy, together with results simultaneous transport measurements. A detailed structural evolution is presented as function applied current density. Local deformation, bidirectional displacement, and reversal are found below Curie temperature increasing discuss probable mechanisms observed features dynamics.
We microscopically demonstrate that the magnetic domain is controllably nucleated and erased in uniformly magnetized wire using a current pulse small fields. Lorentz microscopy performed Permalloy nanowires with in-plane anisotropy. The stochastic nature of magnetization reversal due to spin wave thermal excitations absence field completely disappears turns into deterministic presence field, which enables control. interpret phenomena are associated Zeeman energy stabilization.
We developed a 1 MV field-emission transmission electron microscope. This paper reports details and specifications of the instrument. The microscope was designed to obtain bright coherent beam by using field emission gun equipped with pre-accelerating magnetic lens high-voltage power supply high stability (0.5 ppm min(-1)). Using this microscope, brightness 1.8 x 10(10) A cm(-2) sr(-1) lattice resolution 49.8 pm were attained.
Triple-biprism electron interferometry has been developed to flexibly control all interference parameters, i.e., region (size and shape), fringe spacing, angle. Each filament electrode of the upper middle biprisms is installed in individual image planes objective first magnifying lenses, respectively. One more lower biprism set between crossover plane behind second lens. The azimuth angle filaments at 90°, about 45° for both above filaments. Among many possible optical setups, we chose setup...
Advanced electron microscopy technologies have made it possible to perform precise double-slit interference experiments. We used a 1.2-MV field emission microscope providing coherent waves and direct detection camera system enabling single-electron detections at sub-second exposure time. developed method the experiment by using an asymmetric fabricated focused ion beam instrument operating under "pre-Fraunhofer" condition, different from Fraunhofer condition of conventional Here,...
To utilize magnetic skyrmions, nanoscale vortex-like structures, experimental elucidation of their dynamics against current application in various circumstances such as confined structure and mixture different phases is indispensable. Here, we investigate the current-induced coexistence state skyrmions helical a thin plate B20-type helimagnet FeGe terms situ real-space observation using Lorentz transmission electron microscopy. Current pulses with heights widths were applied, change domain...
$\mathrm{C}{\mathrm{o}}_{3}\mathrm{S}{\mathrm{n}}_{2}{\mathrm{S}}_{2}$ has been attracting attention as a model quasi-2D kagome ferromagnet well ferromagnetic Weyl semimetal. Here, we report the evolution of magnetic domain within function temperature and external field studied by in situ Lorentz microscopy. The structure typical for anisotropy-controlled material was observed, wall (DW) motion found to depend strongly on temperature. It inactive due strong pinning low-temperature range yet...
Journal Article Resolution Assessment of an Aberration Corrected 1.2-MV Field Emission Transmission Electron Microscope Get access Yoshio Takahashi, Takahashi Central Research Laboratory, Hitachi, Ltd., Hatoyama 350-0395, Japan Search for other works by this author on: Oxford Academic Google Scholar Tetsuya Akashi, Akashi Tomokazu Shimakura, Shimakura Toshiaki Tanigaki, Tanigaki Takeshi Kawasaki, Kawasaki Hiroyuki Shinada, Shinada Nobuyuki Osakabe Microscopy and Microanalysis, Volume 21,...
Using cryogenic Lorentz transmission electron microscopy, we investigate the temperature evolution of magnetic structures in single crystal samples K2CuF4 with a phase transition at 6.1 K. This material is known as one candidates for two-dimensional (2D) XY magnet that may exhibit Berezinskii–Kosterlitz–Thouless (BKT) transition. A fine stripe pattern was found period about 120 nm direction along c axis below 7.3 K thin sample plane. Magnetic columns vortices and antivortices separation...
In the samples collected from asteroid Ryugu, magnetite displays natural remanent magnetization due to nebular magnetic field, whereas contemporaneously grown iron sulfide does not display stable magnetization. To clarify this counterintuitive feature, we observed their nanoscale domain structures using electron holography and found that framboidal magnetites have an external field of 300 A m-1, similar bulk value, its stability was enhanced by interactions with neighboring magnetites,...
More realistic simulations of the magnetic field and electron optical phase shift associated to pancake vortices in layered high-${T}_{c}$ superconducting specimen require a number layers larger than 7, practical upper limit set by discrete algebraic approach followed so far. This goal can be achieved resorting continuum approximation screening above below one containing vortex. It is thus possible increase investigate more exotic vortex core structures those represented pancakes pinned at...