A5057476180- Magnetic properties of thin films
- Magnetic Properties and Applications
- Rare-earth and actinide compounds
- Multiferroics and related materials
- Electron and X-Ray Spectroscopy Techniques
- Magnetic and transport properties of perovskites and related materials
- ZnO doping and properties
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic Properties of Alloys
- Advanced Electron Microscopy Techniques and Applications
- Graphene research and applications
- Magneto-Optical Properties and Applications
- Iron-based superconductors research
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Advanced Materials Characterization Techniques
- Nuclear Materials and Properties
- Inorganic Chemistry and Materials
- Diamond and Carbon-based Materials Research
- Silicon Carbide Semiconductor Technologies
- Electronic and Structural Properties of Oxides
- Characterization and Applications of Magnetic Nanoparticles
- Metal and Thin Film Mechanics
- Radioactive element chemistry and processing
Japan Synchrotron Radiation Research Institute
2016-2025
University of Hyogo
2024-2025
SPring-8
2013-2024
Nara Institute of Science and Technology
2017-2022
RIKEN Center for Advanced Photonics
2020
Osaka University
2017
Japan Atomic Energy Agency
2008-2015
Japan Science and Technology Agency
2012
Kyoto University Institute for Chemical Research
2004-2007
Kyoto University
2004-2007
For a long time, there were no efficient ways of controlling antiferromagnets. Quite strong magnetic field was required to manipulate the moments because high molecular and small susceptibility. It also difficult detect orientation since net moment is effectively zero. these reasons, research on antiferromagnets has not been progressed as drastically that ferromagnets which are main materials in modern spintronic devices. Here we show NiO, typical natural antiferromagnet, can indeed be...
AbstractFeNi with the L10-ordered structure is formed over an astronomical timescale in meteorites. In this study, severe plastic deformation using high-pressure torsion (HPT) employed for production of L10 laboratory. Its formation confirmed by X-ray diffraction analysis and transmission electron microscopy. Processing elemental nanopowders HPT effective method phase, which enhanced addition Co to FeNi or annealing after HPT. The phase must be associated diffusion through HPT.Keywords:...
We have studied the electronic structure of Fe-doped ZnO nanoparticles, which been reported to show ferromagnetism at room temperature, by x-ray photoemission spectroscopy, resonant absorption and magnetic circular dichroism (XMCD). From experimental cluster-model calculation results, we find that Fe atoms are predominantly in Fe3+ ionic state with mixture a small amount Fe2+ ions dominant surface region nanoparticles. It is shown temperature nanoparticles primarily originated from...
We investigated the origin of strong magnetic anisotropy energy (MAE) in L10-type ordered FeNi phase by angular-dependent circular dichroism. Our findings showed that orbital moment Fe has a significant angular dependence exhibits maximum value at [001] direction corresponding perpendicular to plane. The calculated uniaxial when considering spin–orbit (SO) interaction shows quantitatively good agreement with volume MAE. concluded 3d electrons results MAE L10-FeNi and ascribe this via...
To understand the hard magnetism of L10-type ordered FeNi alloy, we extracted L10-FeNi phase from a natural meteorite, and evaluated its fundamental solid-state properties: sample composition, magnetic hysteresis, crystal structure electronic structure. We executed multidirectional analyses using scanning electron microscopy with an probe micro-analyzer (SEM-EPMA), superconducting quantum interference device (SQUID), x-ray diffraction (XRD) circular dichroism (MCD). As result, found that...
Substantial upgrades have been made to the beamline BL25SU at SPring-8 for soft X-ray imaging and spectroscopy of solid-state materials. The upgraded consists two branches: a micro-beam branch with high energy resolution, nano-beam small angular divergence. has available use since October 2014, following half year commissioning period. We present here performance parameters, including resolving power, photon flux, focused beam size, which are consistent designed specifications.
A determination of the three-dimensional spin directions in all types domain walls (DWs) antiferromagnetic NiO has been successfully performed by photoemission electron microscopy combined with x-ray magnetic linear dichroism (XMLD), both for $s$- and $p$-polarized light. By comparing azimuthal angle dependence XMLD contrast DWs cluster model calculations which include crystal symmetry full-multiplet splitting, we determine structures ${001}$ T walls, ${011}$...
High-energy-resolution core-level and valence-band photoelectron spectroscopic studies were performed for the heavy Fermion uranium compounds UGe2, UCoGe, URhGe, URu2Si2, UNi2Al3, UPd2Al3, UPt3 as well typical localized itinerant to understand relationship between valence state their spectral line shapes. In addition main high-binding energy satellite structure recognized in spectra of compounds, a shoulder on lower binding side lines nearly was also found. The shapes show systematic...
The electronic structure of the antiferromagnet uranium nitride (UN) has been studied by angle resolved photoelectron spectroscopy using soft X-rays (hn=420-520 eV). Strongly dispersive bands with large contributions from U 5f states were observed in ARPES spectra, and form Fermi surfaces. band as well surfaces paramagnetic phase are explained band-structure calculation treating all electrons being itinerant, suggesting that itinerant description is appropriate for this compound. On other...
Deployments of spherical grids to obtain high energy and angular resolutions for retarding field analyzers (RFAs) having acceptance angles as large or larger than ±45° were explored under the condition using commercially available microchannel plates with effective diameters approximately 100 mm. As a result electron trajectory simulations, deployment three significantly different grid separations instead conventional equidistant showed an resolving power (E/ΔE) 3200 resolution 0.6°. The...
We demonstrate ultrafast magnetization dynamics in a 5d transition metal using circularly-polarized x-ray free electron laser the hard region. A decay time of light-induced demagnetization L1${}_0$-FePt was determined to be $τ_\textrm{Pt} = 0.6\ \textrm{ps}$ time-resolved magnetic circular dichroism at Pt L${}_3$ edge, whereas magneto-optical Kerr measurements indicated for total as $τ_\textrm{total} 0.1\ \textrm{ps}$. transient state with photo-modulated coupling between 3d and elements is...
The electronic structures of the ferromagnetic superconductors $\mathrm{UGe}_2$ and $\mathrm{UCoGe}$ in paramagnetic phase were studied by angle-resolved photoelectron spectroscopy using soft X-rays ($h\nu =400-500$). quasi-particle bands with large contributions from $\mathrm{U}~5f$ states observed vicinity $E_\mathrm{F}$, suggesting that electrons these compounds have an itinerant character. Their overall band explained band-structure calculations treating all as being itinerant....
Photoemission electron microscopy (PEEM) is an imaging technique primarily used to examine local elemental distribution and chemical states. In this study, PEEM was applied skutterudite-based thermoelectric materials investigate the effects of composition material processing. Yb M-edge, Co L-edge, Sb M-edge absorption bonds were selected for analysis. The spectra these elements revealed multiple lines, confirming presence various states in materials. resulting images demonstrate that...
The magnetic properties of as-grown ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ have been investigated by the systematic measurements temperature and field dependent soft x-ray circular dichroism (XMCD). intrinsic XMCD intensity at high temperatures obeys Curie-Weiss law, but a residual spin moment appears already around 100 K, significantly above Curie (${T}_{C}$), suggesting that short-range ferromagnetic correlations are developed ${T}_{C}$. present results also suggest...
Abstract Graphene, a 2D crystal bonded by π and σ orbitals, possesses excellent electronic properties that are promising for next-generation optoelectronic device applications. For these precise understanding of quasiparticle behaviour near the Dirac point (DP) is indispensable because vanishing density states (DOS) DP enhances many-body effects, such as excitonic effects Anderson orthogonality catastrophe (AOC) which occur through interactions many conduction electrons with holes. These...
High quality epitaxial SrCoO x (oxygen deficient 3 ) thin films were grown on (110) DyScO3 substrates by pulsed laser deposition.The disappearance of half order peaks in X‐ray diffraction as well the XAS at O K‐edge indicates an oxygen content ≈ 2.8 films. Magnetization measurements reveal that specific substrate strain suppresses ferromagnetism found corresponding bulk material and emergence antiferromagnetic‐type spin correlation predicted theoretical calculations. Our work demonstrates...
Angle-resolved photoelectron spectroscopy in the Ce 3d-->4f excitation region was measured for paramagnetic state of CeRu2Si2, CeRu2(Si0.82Ge0.18)2, and LaRu2Si2 to investigate changes 4f electron Fermi surfaces around quantum critical point. While difference between CeRu2Si2 experimentally confirmed, a strong 4f-electron character observed band structures consequently indicating delocalized nature electrons both compounds. The absence surface reconstruction across composition suggests that...
The multiferroic $\mathrm{BiFe}{\mathrm{O}}_{3}$ (BFO) as a charge-transfer-type insulator is an interesting system in which to explore correlated electronic conduction. Here, we substitute divalent Ca ions into the parent BFO and apply external electric field at elevated temperatures spatially redistribute spontaneously created oxygen vacancies, thereby generating hole carriers regions of less dense oxygen-vacancy concentrations. X-ray diffraction photoemission spectroscopic measurement are...
FeCo thin films are fabricated by alternate monoatomic layer deposition method on a Cu3Au buffer layer, which in-plane lattice constant is very close to the predicted value obtain large magnetic anisotropy constant. The variation of during process investigated reflection high-energy electron diffraction. domain images also observed photoelectron emission microscope in order microscopically understand structure. As result, element-specific show that Fe and Co moments align parallel. A series...
An endstation dedicated to angle-resolved photoemission spectroscopy (ARPES) using a soft X-ray microbeam has been developed at the beamline BL25SU of SPring-8. To obtain high intensity, this is optimized for measurements under condition grazing beam incidence sample surface, where glancing angle 5° or smaller. A Wolter mirror used focusing X-rays. Even 5°, smallest spot still having sufficient photon flux ARPES almost round on surface and FWHM diameter ∼5 µm. There no need change...
We have derived the three-dimensional band structure and Fermi surfaces of itinerant uranium compound ${\text{UB}}_{2}$ by soft x-ray angle-resolved photoelectron spectroscopy. observed clear energy dispersions with large contribution from $\text{U}\text{ }5f$ states. The obtained results been compared result band-structure calculation within local-density-functional approximation as well de Haas--van Alphen (dHvA) study. qualitative agreement has in size topology dHvA measurement....
Systematic changes in the electronic structure of Bi<sub>1−x</sub>Ca<sub>x</sub>FeO<sub>3−δ</sub>, which are induced by electrically controlled hole carrier doping, observed photoemission electron microscopy (PEEM).