A5088592743- Physics of Superconductivity and Magnetism
- Rare-earth and actinide compounds
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Iron-based superconductors research
- Topological Materials and Phenomena
- Magnetic Properties of Alloys
- Advanced Thermoelectric Materials and Devices
- Advanced Thermodynamics and Statistical Mechanics
- Multiferroics and related materials
- Intellectual Capital and Performance Analysis
- Graphene research and applications
- Catalysis and Oxidation Reactions
- Electronic and Structural Properties of Oxides
- Corporate Taxation and Avoidance
- Superconducting Materials and Applications
Tohoku University
2024
Tokyo University of Science
2018-2022
Kyoto University
2015-2019
The spin susceptibility in strontium ruthenate is shown to undergo an increase when the material goes superconducting, a result variance with most superconductors that we know. This behavior, once predicted for ${}^{3}$He too, surest sign spin-triplet superconductor.
We conducted $^{77}$Se-nuclear magnetic resonance studies of the iron-based superconductor FeSe in fields 0.6 to 19 T investigate superconducting and normal-state properties. The nuclear spin-lattice relaxation rate divided by temperature $(T_1T)^{-1}$ increases below structural transition $T_\mathrm{s}$ but starts be suppressed $T^*$, well above $T_\mathrm{c}(H)$, resulting a broad maximum at $T_\mathrm{p}(H)$. This is similar pseudogap behavior optimally doped cuprate superconductors....
We have studied the superlattices with alternating block layers (BLs) of heavy-fermion superconductor ${\mathrm{CeCoIn}}_{5}$ and conventional-metal ${\mathrm{YbCoIn}}_{5}$ by site-selective nuclear magnetic resonance spectroscopy, which uniquely offers spatially resolved dynamical information. find that presence antiferromagnetic fluctuations is confined to Ce BLs, indicating degrees freedom $f\phantom{\rule{0.28em}{0ex}}\mathrm{electrons}$ are quenched inside Yb BLs. Contrary simple...
We have performed $^{63}\mathrm{Cu}$ nuclear-magnetic-resonance/nuclear-quadrupole-resonance measurements to investigate the magnetic and superconducting (SC) properties on a ``superconductivity dominant'' ($S$-type) single crystal of ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$. Although development antiferromagnetic (AFM) fluctuations down 1 K indicated that AFM criticality was close, Korringa behavior observed below 0.8 K, no anomaly above ${T}_{\mathrm{c}}\ensuremath{\sim}0.6$ K. These...
The layered perovskite ${\mathrm{Sr}}_{2}\mathrm{Ru}{\mathrm{O}}_{4}$ is a very intensively studied superconductor, but its pairing mechanism, which often coupled intimately with magnetic fluctuations in correlated materials, still an open question. Here we present systematic evolution of the Seebeck coefficient Co- and Mn-substituted single crystals, ferromagnetic antiferromagnetic glassy states respectively emerge proximity to superconducting phase parent compound. We find that $S$ divided...
The layered perovskite Sr$_2$RuO$_4$ serves as a model material of the two-dimensional (2D) Fermi liquid but also exhibits various emergent phenomena including non-Fermi-liquid (NFL) behavior under external perturbations such uniaxial pressure and chemical substitutions. Here we present thermoelectric transport electron-doped system Sr$_{2-y}$La$_{y}$RuO$_4$, in which filling-induced Lifshitz transition occurs at Van Hove singularity (VHS) point $y\approx 0.2$. We find that sign...
The layered perovskite <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Sr</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi>RuO</a:mi><a:mn>4</a:mn></a:msub></a:mrow></a:math> serves as a model material of the two-dimensional (2D) Fermi liquid but also exhibits various emergent phenomena including non-Fermi-liquid (NFL) behavior under external perturbations such uniaxial pressure and chemical substitutions. Here we present thermoelectric transport electron-doped system...
We elucidate the ground state nature and low-energy spin dynamics of $s=1/2$ near-perfect kagome antiferromagnet ${\mathrm{YCu}}_{3}{(\mathrm{OD})}_{6+x}{\mathrm{Br}}_{3\ensuremath{-}x}$ ($x=0.5$) using $^{63}\mathrm{Cu}$ nuclear quadrupole resonance (NQR) muon relaxation/rotation ($\ensuremath{\mu}\mathrm{SR}$) techniques. Our combined NQR $\ensuremath{\mu}\mathrm{SR}$ data, along with inverse Laplace transform analysis, reveal an inhomogeneous comprising majority a gapless liquid...
Recent progress in the fabrication techniques of superlattices (SLs) has made it possible to sandwich several-layer-thick block layers (BLs) heavy-fermion superconductor ${\mathrm{CeCoIn}}_{5}$ between conventional-metal ${\mathrm{YbCoIn}}_{5}$ BLs or spin-density-wave-metal ${\mathrm{CeRhIn}}_{5}$ a similar thickness. However, magnetic state each BL, particularly at interface, is not yet understood, as experimental applicable SL system are limited. Here, we report measurements...
Abstract Topological insulators (TIs) are expected to realize new spintronic devices with low dissipative electrical transport. Organic molecule/TI interfaces have been investigated explore the potential of multifunctional organic molecules for TI devices. However, there is no unified understanding interfacial electronic structure. The structure molecular side must be examined fully understand phenomena at interface. Thus, this paper reports investigation interface between electron‐donating...
Since the progress in fabrication techniques of thin films exotic materials such as strongly correlated heavy-fermion compounds, microscopic studies magnetic and electronic properties inside have been needed. Herein, we report observation $^{115}\mathrm{In}$ nuclear quadrupole resonance (NQR) an epitaxial film superconductor ${\mathrm{CeCoIn}}_{5}$, for which field gradient within unit cell well superconducting at zero are evaluated. We find that spin-lattice relaxation rate is excellent...
We have investigated uniaxial and hydrostatic pressure effects on superconductivity in Fe1.07Te0.88S0.12 through magnetic-susceptibility measurements down to 1.8 K. The superconducting transition temperature Tc is enhanced by out-of-plane (uniaxial along the c-axis); onset of reaches 11.8 K at 0.4 GPa. In contrast, reduced in-plane ab-plane) pressure. Taking into account these results, it inferred that Fe1+yTe1-xSx when lattice constant c considerably shrinks. This implies relationship...
We carried out $^{101}\mathrm{Ru}$ nuclear quadrupole resonance (NQR) measurement on superconducting (SC) ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ under zero magnetic field $(H=0)$ and found that the spin-spin relaxation rate $1/{T}_{2}$ is enhanced in SC state. The state $H=0$ effective for detecting slow fluctuations parallel to quantized axis of spin. Our results indicate low-energy perpendicular ${\mathrm{RuO}}_{2}$ plane emerge when superconductivity sets in, which consistent with previous...
We performed nuclear magnetic resonance (NMR) experiments on heavy fermion and conventional metal superlattices CeCoIn5/YbCoIn5. succeeded in identifying the signals arising from CeCoIn5 YbCoIn5 block layers (BLs) by comparing spectra of CeCoIn5/YbCoIn5 superlattices, thin film, film. Furthermore, we found that Ce-BLs could be divided into interfacial inner even one Ce-BL two with different thickness Ce-BLs. A comparison field dependence nuclear-spin lattice relaxation rate 1/T1 indicate...