A5019525180- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Multiferroics and related materials
- Physics of Superconductivity and Magnetism
- Electronic and Structural Properties of Oxides
- Topological Materials and Phenomena
- Inorganic Chemistry and Materials
- Magnetic Properties of Alloys
- MXene and MAX Phase Materials
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Graphene research and applications
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Advanced Thermoelectric Materials and Devices
- Ferroelectric and Piezoelectric Materials
- Magnetic Properties and Synthesis of Ferrites
- Nuclear materials and radiation effects
- 2D Materials and Applications
- Magneto-Optical Properties and Applications
- High-pressure geophysics and materials
- Magnetism in coordination complexes
- Superconductivity in MgB2 and Alloys
RIKEN Center for Emergent Matter Science
2016-2025
RIKEN
2008-2021
Wako University
2021
The University of Tokyo
1999-2019
Sumitomo Chemical (Japan)
2019
Nitto RIKEN (Japan)
2018
Tohoku University
2003-2016
RIKEN Advanced Science Institute
2008-2012
Japan Science and Technology Agency
2004-2009
Istituto Nazionale di Fisica Nucleare, Sezione di Pavia
2007
An electron hopping on non-coplanar spin sites with chirality obtains a complex phase factor (Berry phase) in its quantum mechanical amplitude that acts as an internal magnetic field, and is predicted to manifest itself the Hall effect when it not cancelled. The present combined work of transport measurement, neutron scattering, theoretical calculation provides evidence gigantic anomalous observed Nd2Mo2O7, pyrochlore ferromagnet geometrically frustrated lattice structure, mostly due...
Introducing holes (or partly eliminating electrons) in Mott-Hubbard insulator ${\mathrm{LaTiO}}_{3}$ (with 3${\mathit{d}}^{1}$ configuration) can be carried out by partial substitution of La with Sr, which produces the strongly correlated metallic phase. Systematic variation electronic properties ${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{La}}_{\mathit{x}}$${\mathrm{TiO}}_{3}$ was investigated as a function 3d band filling (x) measurements resistivity, Hall coefficient,...
Skyrmions, topologically protected vortex-like nanometric spin textures in magnets, have been attracting increasing attention for emergent electromagnetic responses and possible technological applications spintronics. In particular, metallic magnets with chiral cubic/tetragonal crystal structure may high potential to host skyrmions that can be driven by low electrical current excitation. However, experimental observations of so far limited below room temperature the specifically MnSi-type...
We present an angle resolved photoemission (ARPES) doping dependence study of the n-type cuprate superconductor Nd_2-xCe_xCuO_4, from half-filled Mott-insulator to T_c=24K superconductor. In Nd2CuO4, we reveal charge-transfer band (CTB) for first time. As electrons are doped into system, this feature's intensity decreases with concomitant formation near-E_F spectral weight. At low doping, Fermi surface is electron-pocket (with volume ~ x) centered at (pi,0). Further leads creation a new...
The mutual control of the electric and magnetic properties a solid is currently great interest because possible application for novel electronic devices. We report on low-magnetic-field (for example, B values +/-30 milliteslas) polarization (P) vector in hexaferrite, Ba2Mg2Fe12O22, which shows helimagnetic spin structure with propagation k0 parallel to [001]. B-induced transverse conical carries P directing perpendicular both k0, accord recently proposed spin-current model. Then, oscillating...
The notion of non-trivial topological winding in condensed matter systems represents a major area present-day theoretical and experimental research. Magnetic materials offer versatile platform that is particularly amenable for the exploration spin solitons real space such as skyrmions. First identified non-centrosymmetric bulk materials, rapidly growing zoology hosting skyrmions related includes compounds, surfaces, thin films, heterostructures, nano-wires nano-dots. This underscores an...
Magnetic and magnetoelectric (ME) properties have been studied for single crystals of Sc-doped M-type barium hexaferrites. Magnetization (M) neutron diffraction measurements revealed that by tuning Sc concentration a longitudinal conical state is stabilized up to above room temperatures. ME shown transverse magnetic field (H) can induce electric polarization (P) at lower temperatures the spin helicity nonvolatile endurable near transition temperature. It was also response (reversal or...
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...
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....
Abstract Reservoir computing is a neuromorphic architecture that may offer viable solutions to the growing energy costs of machine learning. In software-based learning, performance can be readily reconfigured suit different computational tasks by tuning hyperparameters. This critical functionality missing in ‘physical’ reservoir schemes exploit nonlinear and history-dependent responses physical systems for data processing. Here we overcome this issue with ‘task-adaptive’ approach computing....
A neutron scattering study of the Mott-Hubbard insulator LaTiO3 ( T(N) = 132 K) reveals a spin wave spectrum that is well described by nearest-neighbor superexchange constant J 15.5 meV and small Dzyaloshinskii-Moriya interaction D 1.1 meV). The nearly isotropic surprising in view absence static Jahn-Teller distortion could quench orbital angular momentum, it may indicate strong fluctuations. resonant x-ray has uncovered no evidence order LaTiO3.
A large-size single crystal of nearly stoichiometric SrCoO(3) was prepared with a two-step method combining the floating-zone technique and subsequent high oxygen pressure treatment. crystallizes in cubic perovskite structure space group Pm3m, displays an itinerant ferromagnetic behavior Curie temperature 305 K. The easy magnetization axis is found to be along [111] direction, saturation moment 2.5 µ(B)/f.u., accord picture intermediate spin state. resistivity at low temperatures (T)...
Complete magnetoelectric (ME) phase diagrams of orthorhombic $R{\text{MnO}}_{3}$ with and without magnetic moments on the $R$ ions have been established. Three kinds multiferroic ground states, $ab$-cycloidal, $bc$-cycloidal, collinear $E$-type phases, identified by distinct ME responses. The electric polarization dominated symmetric spin exchange $({\mathbit{S}}_{i}\ensuremath{\cdot}{\mathbit{S}}_{j})$ is more than ten times as large that $bc$-cycloidal antisymmetric one...
A well known semiconductor Cd3As2 has reentered the spotlight due to its unique electronic structure and quantum transport phenomena as a topological Dirac semimetal. For elucidating controlling state, high-quality thin films have been highly desired. Here we report development of an elaborate growth technique high-crystallinity high-mobility with controlled thicknesses observation Hall effect dependent on film thickness. With decreasing thickness 10 nm, states exhibit variations such change...
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...
Abstract Magnetic skyrmions, swirling nanometric spin textures, have been attracting increasing attention by virtue of their potential applications for future memory technology and emergent electromagnetism. Despite a variety theoretical proposals oriented towards skyrmion-based electronics (that is, skyrmionics), few experiments succeeded in creating, deleting transferring the manipulation methodologies thus far remained limited to electric, magnetic thermal stimuli. Here, we demonstrate...
A helical spin texture is of great current interest for a host novel spin-dependent transport phenomena. We report rich variety nontrivial helimagnetic phases in the simple cubic perovskite ${\mathrm{SrFeO}}_{3}$ under magnetic fields up to 42 T. Magnetic and resistivity measurements revealed that proper-screw phase proposed can be subdivided into at least five kinds ordered phases. Near multicritical point, an unconventional anomalous Hall effect was found show interpreted as due possible...