Yoshinori Haga
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View article: Local Structure Analysis of Heavy Fermion Ce2Pt6Ga15 with a Honeycomb Structure Using Extended X-Ray Absorption Fine Structure
Local Structure Analysis of Heavy Fermion Ce2Pt6Ga15 with a Honeycomb Structure Using Extended X-Ray Absorption Fine Structure Open
Ce2Pt6Ga15 is a heavy fermion compound near the quantum critical point (QCP). Its crystal structure may exhibit magnetic frustration due to a honeycomb arrangement; however, stacking faults in the crystal hinder structural analysis. As a l…
View article: Magnetic Order in Honeycomb Layered U$_2$Pt$_6$Ga$_{15}$ Studied by Resonant X-ray and Neutron Scatterings
Magnetic Order in Honeycomb Layered U$_2$Pt$_6$Ga$_{15}$ Studied by Resonant X-ray and Neutron Scatterings Open
Antiferromagnetic (AF) order of U$_{2}$Pt$_{6}$Ga$_{15}$ with the ordering temperature $T_{\rm N}$ = 26 K was investigated by resonant X-ray scattering and neutron diffraction on single crystals. This compound possesses a unique crystal st…
View article: Fully gapped pairing state in spin-triplet superconductor UTe <sub>2</sub>
Fully gapped pairing state in spin-triplet superconductor UTe <sub>2</sub> Open
The recently discovered superconductor UTe 2 is a promising candidate for spin-triplet superconductors, but the symmetry of the superconducting order parameter remains highly controversial. Here, we determine the superconducting gap struct…
View article: Quasi-2D Fermi surface in the anomalous superconductor UTe2
Quasi-2D Fermi surface in the anomalous superconductor UTe2 Open
The heavy fermion paramagnet UTe 2 exhibits numerous characteristics of spin-triplet superconductivity. Efforts to understand the microscopic details of this exotic superconductivity have been impeded by uncertainty regarding the underlyin…
View article: Synthesis, Crystal Structure, Local Structure, and Magnetic Properties of Polycrystalline and Single-Crystalline Ce2Pt6Al15
Synthesis, Crystal Structure, Local Structure, and Magnetic Properties of Polycrystalline and Single-Crystalline Ce2Pt6Al15 Open
Asymmetry, such as non-centrosymmetry in the crystal or chiral structure and local symmetry breaking, plays an important role in the discovery of new phenomena. The honeycomb structure is an example of an asymmetric structure. Ce2Pt6Al15 i…
View article: Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$
Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$ Open
Our measurements of $^{125}$Te NMR relaxations reveal an enhancement of electronic spin fluctuations above $μ_0H^*\sim15$ T, leading to their divergence in the vicinity of the metamagnetic transition at $μ_0H_m\approx35$ T, below which fie…
View article: Dramatic elastic response at the critical end point in UTe$_2$
Dramatic elastic response at the critical end point in UTe$_2$ Open
The first-order transition line in the \textit{H-T} phase diagram of itinerant electron metamagnets terminates at the critical end point-analogous to the critical point on the gas-liquid condensation line in the \textit{p-T} phase diagram.…
View article: Fully gapped pairing state in spin-triplet superconductor UTe$_2$
Fully gapped pairing state in spin-triplet superconductor UTe$_2$ Open
Spin-triplet superconductors provide an ideal platform for realizing topological superconductivity with emergent Majorana quasiparticles. The promising candidate is the recently discovered superconductor UTe$ _2$, but the symmetry of the s…
View article: Anomalous vortex dynamics in spin-triplet superconductor UTe$_2$
Anomalous vortex dynamics in spin-triplet superconductor UTe$_2$ Open
The vortex dynamics in the spin-triplet superconductor, UTe$_2$, are studied by measuring the DC electrical resistivity with currents along the $a$-axis under magnetic fields along the $b$-axis. Surprisingly, we have discovered an island r…
View article: Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations
Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations Open
Chiral spin-triplet superconductivity is a topologically nontrivial pairing state with broken time-reversal symmetry, which can host Majorana quasiparticles. The heavy-fermion superconductor UTe 2 exhibits peculiar properties of spin-tripl…
View article: Ferromagnetic Crossover within the Ferromagnetic Order of U$_{7}$Te$_{12}$
Ferromagnetic Crossover within the Ferromagnetic Order of U$_{7}$Te$_{12}$ Open
We investigate the physical properties of a single crystal of uranium telluride U$_{7}$Te$_{12}$. We have confirmed that U$_{7}$Te$_{12}$ crystallizes in the hexagonal structure with three nonequivalent crystallographic uranium sites. The …
View article: First Observation of the de Haas–van Alphen Effect and Fermi Surfaces in the Unconventional Superconductor UTe<sub>2</sub>
First Observation of the de Haas–van Alphen Effect and Fermi Surfaces in the Unconventional Superconductor UTe<sub>2</sub> Open
We report the first observation of the de Haas-van Alphen (dHvA) effect in\nthe novel spin-triplet superconductor UTe2 using high quality single crystals\nwith the high residual resistivity ratio (RRR) over 200. The dHvA frequencies,\nname…
View article: Precise magnetization measurements down to 500 mK using a miniature <sup>3</sup> He cryostat and a closed-cycle <sup>3</sup> He gas handling system installed in a SQUID magnetometer without continuous-cooling functionality
Precise magnetization measurements down to 500 mK using a miniature <sup>3</sup> He cryostat and a closed-cycle <sup>3</sup> He gas handling system installed in a SQUID magnetometer without continuous-cooling functionality Open
We have conducted precise magnetization measurements down to 0.5 K with a miniature 3 He cryostat and a closed-cycle 3 He gas handling system (GHS) for a superconducting quantum interference device magnetometer. The GHS contains two sorpti…
View article: Precise magnetization measurements down to 500 mK using a miniature 3He cryostat and a closed-cycle 3He gas handling system installed in a SQUID magnetometer without continuous-cooling functionality
Precise magnetization measurements down to 500 mK using a miniature 3He cryostat and a closed-cycle 3He gas handling system installed in a SQUID magnetometer without continuous-cooling functionality Open
We have conducted precise magnetization measurements down to 0.5 K with a miniature 3He cryostat and a closed-cycle 3He gas handling system for a commercial superconducting quantum interference device magnetometer [Magnetic Property Measur…
View article: Effect of uranium deficiency on normal and superconducting properties in unconventional superconductor UTe<sub>2</sub>
Effect of uranium deficiency on normal and superconducting properties in unconventional superconductor UTe<sub>2</sub> Open
Single crystals of the unconventional superconductor UTe 2 have been grown in various conditions which result in different superconducting transition temperature as well as normal state properties. Stoichiometry of the samples has been cha…
View article: Slow Electronic Dynamics in the Paramagnetic State of UTe<sub>2</sub>
Slow Electronic Dynamics in the Paramagnetic State of UTe<sub>2</sub> Open
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View article: Observation of Longitudinal Magnetic Fluctuations at a First-Order Ferromagnetic Quantum Phase Transition in UGe<sub>2</sub>
Observation of Longitudinal Magnetic Fluctuations at a First-Order Ferromagnetic Quantum Phase Transition in UGe<sub>2</sub> Open
The connection between ferromagnetic (FM) fluctuations and superconductivity has been well established in FM superconductors UCoGe and URhGe. However, this connection has not been clarified in UGe₂, in which pressure-induced superconductiv…
View article: Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations
Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations Open
Chiral spin-triplet superconductivity is a topologically nontrivial pairing state with broken time-reversal symmetry, which can host Majorana quasiparticles. The recently discovered heavy-fermion superconductor UTe$_2$ exhibits peculiar pr…
View article: Nonmagnetic-magnetic transition and magnetically ordered structure in SmS
Nonmagnetic-magnetic transition and magnetically ordered structure in SmS Open
SmS, a prototypical intermediate valence compound, has been studied by\nperforming high-pressure nuclear magnetic resonance measurements on a\n$^{33}$S-enriched sample. The observation of an additional signal below 15-20 K\nabove a nonmagn…
View article: Electronic structure of URu$_2$Si$_2$ in paramagnetic phase: Three-dimensional angle resolved photoelectron spectroscopy study
Electronic structure of URu$_2$Si$_2$ in paramagnetic phase: Three-dimensional angle resolved photoelectron spectroscopy study Open
The three-dimensional (3D) electronic structure of the hidden order compound URu$_2$Si$_2$ in a paramagnetic phase was revealed using a 3D angle-resolved photoelectron spectroscopy where the electronic structure of the entire Brillouin zon…
View article: Magnetic Penetration Depth of UBe<sub>13</sub> and UPt<sub>3</sub> Derived by DC Magnetization Measurements
Magnetic Penetration Depth of UBe<sub>13</sub> and UPt<sub>3</sub> Derived by DC Magnetization Measurements Open
DC magnetization of heavy-fermion superconductors UBe 13 and UPt 3 has been measured, and the magnetic penetration depth change ∆λ(T ) = λ(T ) -λ(T min ), where T min is the lowest temperature, is derived.For UBe 13 , a single crystal and …
View article: Critical Current Density of the Ferromagnetic Superconductor UGe<sub>2</sub> near the Superconducting Transition Temperature
Critical Current Density of the Ferromagnetic Superconductor UGe<sub>2</sub> near the Superconducting Transition Temperature Open
We have carried out measurements of superconducting critical current density Jc of the ferromagnetic-superconductor UGe2 near the superconducting transition temperature Tsc.In order to reduce Joule heating during the measurement, we have f…