A5002067605- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Multiferroics and related materials
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Magnetic properties of thin films
- Magnetic Properties of Alloys
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Electronic and Structural Properties of Oxides
- Crystallization and Solubility Studies
- Ferroelectric and Piezoelectric Materials
- Organic and Molecular Conductors Research
- Boron and Carbon Nanomaterials Research
- Transition Metal Oxide Nanomaterials
- Magnetism in coordination complexes
- Theoretical and Computational Physics
- Solid-state spectroscopy and crystallography
- Crystal Structures and Properties
- Topological Materials and Phenomena
- Catalysis and Oxidation Reactions
- Crystallography and molecular interactions
- Magneto-Optical Properties and Applications
- X-ray Spectroscopy and Fluorescence Analysis
High Energy Accelerator Research Organization
2016-2025
The Graduate University for Advanced Studies, SOKENDAI
2015-2025
Institute of Materials Structure Science
2012-2024
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2020
Osaka University
2010-2017
Japan Science and Technology Agency
2000-2016
University of Tsukuba
2014
Tohoku University
2003-2011
Centre National de la Recherche Scientifique
2011
Institut Charles Gerhardt Montpellier
2011
Magnetic skyrmion textures are realized mainly in non-centrosymmetric, e.g. chiral or polar, magnets. Extending the field to centrosymmetric bulk materials is a rewarding challenge, where released helicity / vorticity degree of freedom and higher density result intriguing new properties enhanced functionality. We report here on experimental observation lattice (SkL) phase with large topological Hall effect an incommensurate helical pitch as small 2.8 nm metallic Gd3Ru4Al12, which...
A series of cyanide bridged Fe-Co molecular squares, [Co(2)Fe(2)(CN)(6)(tp*)(2)(dtbbpy)(4)](PF(6))(2)·2MeOH (1), [Co(2)Fe(2)(CN)(6)(tp*)(2)(bpy)(4)](PF(6))(2)·2MeOH (2), and [Co(2)Fe(2)(CN)(6)(tp)(2)(dtbbpy)(4)](PF(6))(2)·4H(2)O (3) (tp = hydrotris(pyrazol-1-yl)borate, tp* hydrotris(3,5-dimethylpyrazol-1-yl)borate, bpy =2,2'-bipyridine, dtbbpy =4,4'-di-tert-butyl-2,2'-bipyridine), were prepared by the reactions [Fe(CN)(3)(L)](-) (L tp or tp*) with Co(2+) bidentate ligands (bpy dtbbpy) in...
Geometrically frustrated magnets provide abundant opportunities for discovering complex spin textures, which sometimes yield unconventional electromagnetic responses in correlated electron systems. It is theoretically predicted that magnetic frustration may also promote a topologically nontrivial state, i.e., skyrmions, are nanometric vortices. Empirically, however, skyrmions essentially concomitant with noncentrosymmetric lattice structures or interfacial-symmetry-breaking heterostructures....
Quantum transport of quasi–two-dimensional Dirac fermions is largely controlled by magnetic order in a layered magnet.
Magnetic skyrmion is a topologically stable particle-like swirling spin texture potentially suitable for high-density information bit, which was first observed in noncentrosymmetric magnets with Dzyaloshinskii-Moriya interaction. Recently, nanometric has also been discovered centrosymmetric rare-earth compounds, and the identification of their formation mechanism further search nontrivial textures are highly demanded. Here, magnetic structures prototypical skyrmion-hosting tetragonal magnet...
We report a ferroelectric transition driven by the off-centering of magnetic ${\mathrm{Mn}}^{4+}$ ions in antiferromagnetic Mott insulators ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{x}{\mathrm{MnO}}_{3}$ with perovskite structure. As $x$ increases, lattice shows typical soft-mode dynamics, as revealed momentum-resolved inelastic x-ray scattering and far-infrared spectroscopy, ferroelectricity up for $x\ensuremath{\ge}0.45$. The observed polarization is comparable to that prototypical...
A hydrogen bond (H-bond) is one of the most fundamental and important noncovalent interactions in chemistry, biology, physics, all other molecular sciences. Especially, dynamics a proton or atom H-bond has attracted increasing attention, because it plays crucial role (bio)chemical reactions some physical properties, such as dielectricity conductivity. Here we report unprecedented H-bond-dynamics-based switching electrical conductivity magnetism H-bonded purely organic conductor crystal,...
The topological Hall effect (THE) and its thermoelectric counterpart, the Nernst (TNE), are hallmarks of skyrmion lattice phase (SkL). We observed giant TNE SkL in centrosymmetric Gd_{2}PdSi_{3}, comparable magnitude to largest anomalous signals ferromagnets. Significant enhancement (suppression) THE occurs when doping electrons (holes) Gd_{2}PdSi_{3}. On electron-doped side, conductivity approaches characteristic threshold ∼1000 (Ω cm)^{-1} for intrinsic regime. use filling-controlled...
In this letter we report lattice dimerization and spin-gap formation of NaV 2 O 5 below its spin-Peierls transition temperature T sp =35.3 K, in which there are V 4+ ( S =1/2) linear chains along the b axis orthorhombic structure. A single-crystal X-ray scattering experiment shows superlattice reflections with a modulation vector q =(1/2, 1/2, 1/4) . Inelastic neutron from powder sample at =7 K clearly demonstrates gap energy 9.8 meV | Q |=1.0 Å -1 corresponding to reciprocal point (1, 0).
Antiferroquadrupolar (AFQ) ordering has been conjectured in several rare-earth compounds to explain their anomalous magnetic properties. No direct evidence for AFQ ordering, however, reported. Using the resonant x-ray scattering technique near Dy L(III) absorption edge, we have succeeded observing order parameter DyB2C2 and analyzing energy polarization dependence. The much weaker coupling between orbital degrees of freedom lattice 4f electron systems than 3d makes them an ideal platform...
Perpendicular magnetic anisotropy (PMA) of cobalt-ferrite CoxFe3-xO4 (x = 0.75 and 1.0) epitaxial thin films grown on MgO (001) by a reactive magnetron sputtering technique was investigated. The saturation magnetization found to be 430 emu/cm3 for x 0.75, which is comparable that bulk CoFe2O4 (425 emu/cm3). Torque measurements afforded PMA constants Kueff=9.0 Merg/cm3 (Ku=10.0 Merg/cm3) Kueff=9.7 1.0, respectively. value Kueff extrapolated using Miyajima's plot as high 14.7 1.0. in-plane...
For the skyrmion-hosting intermetallic ${\mathrm{Gd}}_{2}{\mathrm{PdSi}}_{3}$ with centrosymmetric hexagonal lattice and triangular net of rare earth sites, we report a thorough investigation magnetic phase diagram. Our work reveals an isotropic value critical field for all orientations, where ordering vector $\mathbf{q}$ is depinned from its preferred directions in basal plane. The bulk nature skyrmion other phases was evidenced by specific-heat measurements. Resistivity anisotropy, likely...
Topological swirling spin textures, such as skyrmions and merons, have recently attracted much attention a unique building block for high-density magnetic information devices. The controlled transformation among different types of quasi-particles is an important challenge, while it was previously achieved only in few non-centrosymmetric systems characterized by Dzyaloshinskii-Moriya interaction. Here, we report experimental discovery multi-step topological transitions variety meron skyrmion...
Magnetic skyrmions are particle-like spin-swirling objects ubiquitously realized in magnets.They topologically stable chiral kinks composed of multiple modulation waves spiral spin structures, where the helicity each is usually selected by antisymmetric exchange interactions noncentrosymmetric crystals.We report an experimental observation a distorted triangular lattice polar tetragonal magnet EuNiGe3, reflecting strong coupling with lattice.Moreover, through resonant x-ray diffraction, we...
The magnetic skyrmion lattice is a crystallization of spin-swirling particle-like objects composed multiple helimagnetic modulation waves with the same helicity (sense rotation). Despite widespread observation this spectacular structure, experimental verification unified has not yet been achieved. Using circularly polarized resonant x-ray diffraction, authors study here triangular in chiral helimagnet EuPtSi and demonstrate that indeed unified. This method great potential for unraveling...
Under zero magnetic field, a quadrupolar order parameter at \(\mbi{q}_{Q}=(\frac{1}{2},\frac{1}{2},\frac{1}{2})\) in typical antiferro-quadrupole (AFQ) ordering compound CeB 6 has been observed for the first time by means of resonant X-ray scattering (RXS) technique. The RXS is 2 p →5 d dipole transition energy Ce L 3 -edge. Using this technique to observe pure AFQ state, phase diagram Phase II determined.
Synchrotron x-ray-diffraction experiments have been carried out in a perovskite-type vanadium oxide ${\mathrm{YVO}}_{3}$ to elucidate orbital ordering of the system. The change from C- G-type at lower magnetic transition temperature was strongly suggested. long-range appears also high-temperature paramagnetic phase. Azimuthal-angle dependence superlattice reflections indicates that for both orbital-ordering phases occupation is approximately ${d}_{\mathrm{xy}}^{1}{d}_{\mathrm{yz}}^{1}$ and...
We investigated the magnetic structure of an orthorhombic YMnO(3) thin film by resonant soft x-ray and hard diffraction. observed a temperature-dependent incommensurate reflection below 45 K commensurate lattice-distortion 35 K. These results demonstrate that ground state is composed coexisting E-type cycloidal states. Their different ordering temperatures clarify origin large polarization to be caused antiferromagnetic states in film.
We have investigated the Co-3d spin-orbital state in a thin film of perovskite LaCoO3 to clarify origin strain induced spontaneous magnetization (T(C)=94 K) by means x-ray diffraction, optical spectroscopy, and measurements. A lattice distortion with propagation vector (1/4 -1/4 1/4) an anomalous activation phonons coupled orbital are observed below 126 K. Combined azimuthal angle analysis superlattice reflection, we propose that ordering promoted epitaxial produces unique ferrimagnetic structure.
We report magnetotransport properties for epitaxial thin films of SrFeO${}_{3}$ and SrFe${}_{0.99}$Co${}_{0.01}$O${}_{3}$ with possible skyrmion-related spin textures. Resonant soft x-ray diffraction measurements revealed formation helical structures both samples ($Q//\ensuremath{\langle}111\ensuremath{\rangle}$). From we found several distinct helimagnetic phases multiple/single $Q$ vectors. A steep suppression Hall resistivity is observed above the critical field to reach high-field...
Magnetic order in the magnetic-field-induced so-called A phase of cubic chiral antiferromagnet EuPtSi was investigated by resonant X-ray scattering (RXS) near Eu L2 absorption edge. The high-intensity RXS signal revealed triple-q magnetic a field applied along [111] direction. is described three propagation vectors lying on plane normal to direction: \(\boldsymbol{{q}}_{1} = ( - \delta _{3},\delta _{1},\delta _{2})\), \(\boldsymbol{{q}}_{2} _{2},\delta _{3}, _{1})\), and...