A5082523771- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Magnetic properties of thin films
- Magnetism in coordination complexes
- Multiferroics and related materials
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Magnetic Properties of Alloys
- Topological Materials and Phenomena
- Porphyrin and Phthalocyanine Chemistry
- Organic and Molecular Conductors Research
- Theoretical and Computational Physics
- Characterization and Applications of Magnetic Nanoparticles
- Graphene research and applications
- Quantum and electron transport phenomena
- High-pressure geophysics and materials
- Metal-Organic Frameworks: Synthesis and Applications
- ZnO doping and properties
- Magneto-Optical Properties and Applications
- Inorganic Fluorides and Related Compounds
- Magnetic Properties and Synthesis of Ferrites
- Transition Metal Oxide Nanomaterials
Osaka University
2016-2025
Tohoku University
2024
High Magnetic Field Laboratory
2023
Osaka Prefecture University
2017-2018
Hiroshima University
2015
Osaka Kyoiku University
2013
Suzuki (Japan)
2010
Japan Advanced Institute of Science and Technology
2004-2006
We have investigated magnetic and transport properties of the {\it kagom\'{e}-bilayer} ferromagnet Fe$_{3}$Sn$_{2}$. A soft ferromagnetism a large anomalous Hall effect are observed. The saturated resistivity Fe$_{3}$Sn$_{2}$ is 3.2 $\mu\Omega$cm at 300 K, which almost 20 times higher than that typical itinerant-ferromagnets such as Fe Ni. coefficient $R_{{\rm s}}$ 6.7$\times10^{-9}$ $\Omega$cm/G three orders magnitude larger pure Fe. obeys an unconventional scaling to longitudinal...
We investigated the transport properties of BaFe${}_{2}$As${}_{2}$ single crystals before and after annealing with BaAs powder. The remarkably improves properties, in particular, magnitude residual resistivity, which decreases by a factor more than 10. From resistivity measurement on detwinned crystals, we found that anisotropy in-plane is diminished annealing, indicative dominant contributions to charge from carriers isotropic high mobility below magnetostructural transition temperature...
We investigate the magnetic torque and magnetoresistance (MR) responses in oblique fields micrometer-sized specimens of hexagonal chiral crystal ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$. The results exhibit hysteresis over a wide range applied field angles, while reversible behavior appears only when is closely aligned to helical axis crystal. Stepwise changes MR detected region indicate existence solitons fields. A phase diagram derived from experimental results, stability phases, such as...
We have performed electrical resistivity measurements of a polycrystalline sample FeSe 0.25 Te 0.75 , which exhibits superconductivity at T c ∼14 K, in magnetic fields up to 55 determine the upper critical field µ 0 H c2 . In this compound, very large slopes onset, mid-point, zero-resistivity temperatures on are determined be -13.7, -10.1, and -6.9 T/K, respectively. The observed ( )s compound considerably smaller than those expected from Werthamer–Helfand–Hohenberg model, manifesting Pauli...
Unconventional features of relativistic Dirac/Weyl quasiparticles in topological materials are most evidently manifested the two-dimensional quantum Hall effect (QHE), whose variety is further enriched by their spin and/or valley polarization. Although its extension to three dimensions has been long sought and inspired theoretical proposals, material candidates have lacking. Here, we discovered valley-contrasting spin-polarized Dirac fermions a multilayer form bulk antiferromagnet...
A 3D bulk metamaterial (MM) containing amorphous multilayered split-ring resonators is proposed, fabricated, and evaluated. Experimentally, the effective refractive index engineered via MM, with a contrast of 0.118 across frequency span from 0.315 to 0.366 THz changing at slope 2.314 per within this range. Additionally, MM exhibits optical isotropy respect polarization. Moreover, peak transmission dispersion are tailored by adjusting density resonators. Compared reported conventional...
The theoretical Kondo necklace model, which simplifies the lattice model by focusing on spin degrees of freedom, provides a valuable framework for understanding spin-related quantum phenomena. However, it has not been applied to real materials until now. We present realization spin-1/2 anisotropic using complex radical and Co spins. Electron resonance reveals <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>g</a:mi></a:math> values an Ising-type exchange interaction with spin....
We have succeeded in preparing single crystals of CaCu3(OH)6Cl2 ∙ 0.6H2O, a candidate for the S = 1/2 Kagome lattice antiferromagnet. Magnetic properties compound are dominated by nearest neighbor antiferromagnetic interaction J1, and next ferromagnetic J2 an Jd across hexagon, which is different from related compounds Kapellasite Haydeeite with J1. susceptibility exhibits sudden increase below 13 K cusp anomaly at T* 7.2 ab-plane, whereas only moderate enhancement observed along c-axis. A...
Magnets, with topologically-nontrivial Dirac/Weyl points, have recently attracted significant attention owing to the unconventional physical properties, such as large anomalous Hall effects. However, they typically a high carrier density and complicated band structure near Fermi energy. In this study, we report degenerate magnetic semiconductor EuMg$_2$Bi$_2$, which exhibits single valley at $\Gamma$ point, where field-tunable Weyl points form via exchange interaction local Eu spins. By...
We observe a disappearance of the $1/3$ magnetization plateau and striking change magnetic configuration under moderate doping model triangular antiferromagnet $\mathrm{RbFe}({\mathrm{MoO}}_{4}{)}_{2}$. The reason is an effective lifting degeneracy mean-field ground states by random potential impurities, which compensates, in low-temperature limit, fluctuation contribution to free energy. These results provide direct experimental confirmation origin state real frustrated system. least...
We present a new model compound with the S = 1/2 frustrated square lattice composed of charge-transfer salt (o-MePy-V)PF6. Ab initio calculations indicate formation an lattice, in which six types nearest-neighbor ferromagnetic- and antiferromagnetic interactions cause frustration. By applying magnetic field, we observe unusually gradual increase magnetization subsequent 1/2-plateau-like behavior. A numerical analysis using tensor network method qualitatively demonstrates such behaviors...
The 5d transition-metal oxides have a unique electronic structure dominated by strong spin-orbit coupling and hence they can be an intriguing platform to explore spin-current physics. Here, we report on room-temperature generation of torque (SOT) from conductive iridium oxide, IrO2. By measuring second-harmonic Hall resistance Ni81Fe19/IrO2 bilayers, find both dampinglike fieldlike SOTs. former is larger than the latter, enabling easier control magnetization. We also observe that SOT...
Exotic spin-multipolar ordering in spin transition metal insulators has so far eluded unambiguous experimental observation. A less studied, but perhaps more feasible fingerprint of multipole character emerges the excitation spectrum form quadrupolar transitions. Such multipolar excitations are desirable as they can be manipulated with use light or electric field and captured by means conventional techniques. Here we study single crystals multiferroic...
We succeeded in growing single crystals of EuCu2(Ge1−xSix)2 (x = 0–1) by the Bridgman method using a Mo crucible and measured electrical resistivity, specific heat, magnetic susceptibility, magnetization, together with resistivity under pressure. compounds follow Doniach phase diagram as function x content. Namely, exhibit antiferromagnetic ordering at Néel temperature TN 15 K EuCu2Ge2 0), maximum \( \simeq \) 20 0.5, → 0 0.7, moderate heavy-fermion state 0.8 1 (EuCu2Si2). The present result...
We successfully synthesized a verdazyl-based complex, ($p$-Py-V-$p$-CN)$_2$[Cu(hfac)$_2$]. Molecular orbital calculations reveal that three types of antiferromagnetic (AF) interactions are involved in the formation spin-1/2 distorted octagonal lattice composed verdazyl radical and Cu spins. The magnetic properties compound exhibited contributions from AF correlations phase transition to an ordered state at approximately $T_{\rm{N}}$ = 2.5 K. Below $T_{\rm{N}}$, we observed $T^2$ dependence...
The ferrimagnetic spin-1/2 chain composed of alternating Ising and Heisenberg spins in an arbitrarily oriented magnetic field is exactly solved using the spin-rotation transformation transfer-matrix method.It shown that low-temperature magnetization process depends basically on a spatial orientation field.A sharp stepwise curve with marked intermediate plateau, which emerges for applied along easy-axis direction spins, becomes smoother plateau shrinks if external tilted from direction.The...
We have discovered a novel candidate for spin liquid state in ruthenium oxide composed of dimers $S = $ 3/2 spins Ru$^{5+}$,Ba$_3$ZnRu$_2$O$_9$. This compound lacks long range order down to 37 mK, which is temperature 5000-times lower than the magnetic interaction scale around 200 K. Partial substitution Zn can continuously vary ground from an antiferromagnetic spin-gapped through state. indicates that spin-liquid emerges delicate balance inter- and intra-dimer interactions, dimer plays...
FeSn is an antiferromagnet with the Néel temperature TN = 370 K, while CoSn a Pauli paramagnet. We grew high-quality single crystals of and hexagonal structure mainly studied electronic state by measuring electrical resistivity, specific heat, magnetic susceptibility, magnetization, de Haas–van Alphen (dHvA) effect. The Fermi surface properties in antiferromagnetic were clarified dHvA experiment energy band calculation. main found to be cylindrical along [0001] direction, possessing...
We successfully synthesize single crystals of the verdazyl radical $\ensuremath{\alpha}\text{\ensuremath{-}}2,3,5\text{\ensuremath{-}}{\mathrm{Cl}}_{3}$-V. Ab initio molecular orbital calculations indicate that two dominant antiferromagnetic interactions, ${J}_{1}$ and ${J}_{2}$ $(\ensuremath{\alpha}={J}_{2}/{J}_{1}\ensuremath{\simeq}0.56)$, form an $S=1/2$ distorted square lattice. explain magnetic properties based on lattice Heisenberg antiferromagnet using quantum Monte Carlo method,...
We have investigated the fluorine-doping dependence of lattice constants, transports and specific heat for polycrystalline LaFePO 1- x F . doping slightly monotonically decreases in-plane parameter. In normal state, electrical resistivity at low temperature is proportional to square electronic coefficient has large value, indicating existence moderate electron–electron correlation in this system. Hall magnitude, shows dependence, carrier density multiple carriers Temperature upper critical...