A5032928244- Magnetic properties of thin films
- Advanced Chemical Physics Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Catalytic Processes in Materials Science
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- ZnO doping and properties
- Graphene research and applications
- Advanced X-ray Imaging Techniques
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Advanced Condensed Matter Physics
- Molecular Junctions and Nanostructures
- Heusler alloys: electronic and magnetic properties
- Catalysis and Oxidation Reactions
- Magnetic Properties of Alloys
- Multiferroics and related materials
- Electrocatalysts for Energy Conversion
- Surface and Thin Film Phenomena
- Surface Chemistry and Catalysis
- Magnetic Properties and Synthesis of Ferrites
- nanoparticles nucleation surface interactions
Institute of Materials Structure Science
2013-2025
The University of Tokyo
2003-2024
High Energy Accelerator Research Organization
2015-2024
The Graduate University for Advanced Studies, SOKENDAI
2015-2024
University of Tsukuba
2024
Japan Science and Technology Agency
2008-2022
Tohoku University
2022
Spintronics Research Network of Japan
2022
National Institutes for Quantum Science and Technology
2022
National Institute for Materials Science
2006-2019
The adsorption structure of methylthiolate (CH3S) adsorbed on Au(111), a long-standing controversial issue, has been unambiguously determined by scanned-energy and scanned-angle S 2p photoelectron diffraction. molecules are found to occupy atop sites with S-Au distance 2.42 +/- 0.03 A. angular distribution the photoelectrons due forward scattering reveals that S-C bond is inclined approximately 50 degrees from surface normal towards both [211] [121] (nearest-neighbor thiolate) directions.
The CO oxidation reaction on the Pd(111) model catalyst at various temperatures (200–400 °C) under hundreds mTorr pressure conditions has been monitored by in situ ambient X-ray photoelectron spectroscopy and mass spectroscopy. In observation of revealed that surface is covered molecules a lower temperature (200 °C), while higher (300–400 several oxide phases are formed surface. We found reactivity enhanced presence significantly suppressed formation cluster PdO bulk oxide. titration...
The electronic structure and spin magnetism for few-layer-graphene nanoribbons synthesized by chemical vapor deposition have been investigated using near-edge x-ray absorption fine (NEXAFS) electron-spin resonance (ESR). For the pristine sample, a prepeak was observed below ${\ensuremath{\pi}}^{\ensuremath{\ast}}$ peak close to Fermi level in NEXAFS, indicating presence of additional states level. intensity this decreased with increasing annealing temperature disappeared after above...
Angle-resolved photoemission spectroscopy using a micro-focused beam spot [micro-angle-resolved (ARPES)] is becoming powerful tool to elucidate key electronic states of exotic quantum materials. We have developed versatile micro-ARPES system based on the synchrotron radiation focused with Kirkpatrick-Baez mirror optics. The mirrors are monolithically installed stage, which driven five-axis motion, and vibrationally separated from ARPES measurement system. Spatial mapping Au photolithography...
Abstract Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure Mn 4 Bi 2 Te 7 /Bi 3 where multiple layers are inserted into topmost quintuple layer of original insulator . A massive Dirac cone (DC) with gap 40–75 meV at 16 K observed. By tracing temperature evolution, this shown gradually decrease increasing blunt transition from massless DC...
The spin, in-plane and out-of-plane orbital magnetic dipole moments of almost purely interfacial Co atoms were directly determined for Au/2-monolayer nanoclusters/Au(111) by angle-dependent circular x-ray dichroism (MCXD) measurements. field- temperature-dependent MCXD evidences a ferromagnetic(FM)-to-superparamagnetic phase transition in single-domain clusters with decreasing size. are remarkably enhanced as compared bulk values, verifying theoretical predictions. FM show strong...
Catalytic CO oxidation reaction on a Pd(100) single-crystal surface under several hundred mTorr pressure conditions has been studied by ambient X-ray photoelectron spectroscopy and mass spectroscopy. In-situ observation of the reveals that two pathways switch over alternatively depending temperature. At lower temperatures, is covered molecules CO2 formation rate low, indicating poisoning. higher temperatures above 190 °C, an O-Pd-O trilayer oxide phase formed drastically increases. It likely...
We report on the present status of a vacuum ultraviolet and soft X-ray undulator beamline, BL-13A, located at Photon Factory. BL-13A is mainly dedicated to study organic thin films adsorbed well-defined surfaces, using angle-resolved photoelectron spectroscopy (ARPES), (XPS), absorption (XAS). The photon-energy resolution (E/ΔE) estimated be about 10000 photon energy 64 eV with an exit-slit width 30 μm. intensity 2.9 × 1012 5.6 108 photons/s for energies 30-1600 100 μm ring current 450 mA....
In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure solids, we have developed a scanning photoelectron microscope system with capability depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this 3D nano-ESCA. For focusing x-ray, Fresnel zone plate diameter 200 μm and an outermost width 35 nm is used. obtain angular dependence spectra depth-profile without rotating sample, adopted modified VG Scienta R3000...
The design and commissioning of a new soft X‐ray beamline, BL‐16A, at the Photon Factory is presented. beamline consists pre‐focusing mirror, an entrance slit, variable‐included‐angle varied‐line‐spacing plane grating monochromator, post‐focusing system as usual, provides circularly linearly polarized X rays in energy range 200–1500 eV with APPLE‐II type undulator. procedure for optics described detail, especially check focal position zero‐th order diffracted rays.
We investigated the high-density CO adsorption phase formed on a Pt(111) surface when exposed to gas of pressure ranging from UHV 100 mTorr using near-ambient-pressure (NAP)-XPS. Combined results NAP-XPS measurements and DFT calculations reveal structure molecules in dense overlayer, which is stable under realistic conditions.
The intermetallic compound Fe1−xCoxSi exhibits helical magnetic order for 0.05<x<0.8, whereas its orbital angular momentum, which contributes to the occurrence of Dzyaloshinskii-Moriya (DM) interactions, has not yet been verified systematically. According previous neutron experiments, magnitude DM interaction maximum at around x=0.25, and that x=0.50 was approximately 60% x=0.25. We conducted soft x-ray circular dichroism spectroscopy on Fe L2,3 Co edges below critical temperature Tc in...
Spin-valley magnetic ordering is restricted to layered van der Waals type transition-metal dichalcogenides with temperatures below 55 K. Recent theoretical studies on non-van structures have predicted spin-valley polarization induced semiconducting ferromagnetic ground states, but experimental validation missing. We report high-Curie temperature (TC ~ 225 K) metallic ferromagnetism spontaneous in monolayer Cr2Se3 graphene. Angle-resolved photoemission spectroscopy (ARPES) reveals systematic...
The mechanism of degradation flash EEPROM cell characteristics caused by program operation with the channel hot electron injection after program/erase (P/E) cycles are investigated. To clarify relation between and oxide damage such as interface-states charges, charge-pumping (CP) technique, transconductance (G/sub m/) measurements endurance performed. In degradation, a reduction into floating gate G/sub m/ should be considered separately. is found to mainly located in drain overlap region,...
A depth-resolved technique in the x-ray magnetic circular dichroism (XMCD) has been developed and applied to Fe/Cu(100) Fe/Ni/Cu(100) order observe depth profile directly. It was confirmed that surface two layers of 7 ML are ferromagnetically coupled, while inner spin density wave (SDW) state at 130 K. The enables one extract XMCD spectra from ferromagnetic (FM) SDW regions separately, indicating FM/SDW interface an antiparallel coupling, region bulk-like feature. For Fe/Ni/Cu(100), we have...
Ga${}^{+}$ irradiation-induced changes in magnetic anisotropy and crystalline structure of a Pt/Co/Pt ultrathin film are investigated by means x-ray circular dichroism (XMCD) extended absorption fine (EXAFS) techniques. The XMCD analysis shows large orbital moment difference between out-of-plane in-plane directions, which corresponds to perpendicular (PMA), at moderate fluences, while further increased fluences reduce the resulting magnetization. From EXAFS analysis, enhancement PMA is...
A room-temperature skyrmion-hosting compound ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4}$ has been examined by means of soft x-ray absorption spectroscopy, resonant small-angle scattering, and extended reference holography. An element-selective study was performed exciting the $2p$-to-$3d$ transitions near Co Mn ${L}_{2,3}$ edges. By utilizing coherence beams element-specific real-space distribution local magnetization at different temperatures reconstructed using iterative phase...