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Tamura, Kazuhisa
Journal of Physical Chemistry C, 127(46), p.22733 - 22739, 2023/11
Times Cited Count:0 Percentile:0(Chemistry, Physical)The underpotential deposition of Bi on Au(111) electrode in 1 M HClO solution and 1-butyl-3-methylimidazolium tetrafluoroborate was investigated using visible light reflectance measurement and surface X-ray scattering techniques. The electrosorption valency of the UPD reaction of Bi was elucidated and it was found that in both 1 M HClO and 1-butyl-3-methylimidazolium tetrafluoroborate the electrosorption valency was smaller than 3, but the detail process in the UPD reaction was different between in two electrolytes. The difference may be originated from the difference in the solvation status of Bi rather than the electrical double layer structure.
Yamaguchi, Toshio*; Fukuyama, Nami*; Yoshida, Koji*; Katayama, Yoshinori*; Machida, Shinichi*; Hattori, Takanori
Liquids, 3(3), p.288 - 302, 2023/09
We report the structure of an aqueous 2 mol/kg MgCl solution at pressures from 0.1 MPa to 4 GPa and temperatures from 300 to 500 K revealed by X-ray and neutron scattering measurements. The scattering data are analyzed by empirical potential structure refinement (EPSR) modeling to derive the pair distribution functions, coordination number distributions, angle distributions, and spatial density functions as a function of pressure and temperature. Mg forms rigid solvation shells extended to the third shell; the first solvation shell of six-fold octahedral coordination with about six water molecules at 0 GPa transforms into about five water molecules and one Cl due to the formation of the contact ion pairs in the GPa pressure range. The Cl solvation shows a substantial pressure dependence; the coordination number of a water oxygen atom around Cl increases from 8 at 0.1 MPa/300 K to 10 at 4 GPa/500 K. The solvent water transforms the tetrahedral network structure at 0.1 MPa/300 K to a densely packed structure in the GPa pressure range; the number of water oxygen atoms around a central water molecule gradually increases from 4.6 at 0.1 MPa/298 K to 8.4 at 4 GPa/500 K.
Kaneko, Koji; Cheung, Y. W.*; Hu, Y.*; Imai, Masaki*; Tanioku, Yasuaki*; Kanagawa, Hibiki*; Murakawa, Joichi*; Moriyama, Kodai*; Zhang, W.*; Lai, K. T.*; et al.
JPS Conference Proceedings (Internet), 30, p.011032_1 - 011032_6, 2020/03
Murai, Naoki; Fukuda, Tatsuo; Nakajima, Masamichi*; Kawamura, Mitsuaki*; Ishikawa, Daisuke*; Tajima, Setsuko*; Baron, A. Q. R.*
Physical Review B, 101(3), p.035126_1 - 035126_6, 2020/01
Times Cited Count:5 Percentile:32.24(Materials Science, Multidisciplinary)We report an inelastic X-ray scattering investigation of phonons in FeSe superconductor. Comparing the experimental phonon dispersion with density functional theory (DFT) calculations in the non-magnetic state, we found a significant disagreement between them. A better overall agreement was obtained by allowing for spin-polarization in DFT calculations, despite the absence of magnetic order in FeSe. This calculation gives a realistic approximation, at DFT level, of the disordered paramagnetic state of FeSe, in which strong spin fluctuations are present.
Tabata, Chihiro*; Matsumura, Takeshi*; Nakao, Hironori*; Michimura, Shinji*; Kakihana, Masashi*; Inami, Toshiya*; Kaneko, Koji; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 88(9), p.093704_1 - 093704_5, 2019/09
Times Cited Count:34 Percentile:88.41(Physics, Multidisciplinary)Cheung, Y. W.*; Hu, Y. J.*; Imai, Masaki*; Tanioku, Yasuaki*; Kanagawa, Hibiki*; Murakawa, Joichi*; Moriyama, Kodai*; Zhang, W.*; Lai, K. T.*; Yoshimura, Kazuyoshi*; et al.
Physical Review B, 98(16), p.161103_1 - 161103_5, 2018/10
Times Cited Count:19 Percentile:66.85(Materials Science, Multidisciplinary)Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Kuzushita, Kaori; Inami, Toshiya; Owada, Kenji; Maekawa, Sadamichi*; Masui, Takahiko*; Tajima, Setsuko*; et al.
AIP Conference Proceedings 850, p.445 - 446, 2006/09
Mott gap excitations in the optimally doped high- superconductor YBaCuO ( = 93 K) have been studied by the resonant inelastic X-ray scattering method. Anisotropic spectra in the -plane are observed in a twin-free crystal. The excitation from the one-dimensional CuO chain is enhanced at 2 eV near the zone boundary of the direction, while the excitation from the CuO plane is broad at 1.5-4 eV and almost independent of the momentum transfer. Theoretical calculation based on the one-dimensional and two-dimensional Hubbard model reproduces the observed spectra when different values of the on-site Coulomb energy are assumed. The Mott gap of the CuO chain site is found to be much smaller than that of the CuO plane site.
Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Maekawa, Sadamichi*; Hoesch, M.; Kuzushita, Kaori; Inami, Toshiya; Tsubota, Masami; Yamada, Kazuyoshi*; et al.
AIP Conference Proceedings 850, p.403 - 404, 2006/09
We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the electron-doped high- superconductor NdCeCuO. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with -dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model.
Ishii, Kenji; Inami, Toshiya; Owada, Kenji; Kuzushita, Kaori; Mizuki, Junichiro; Murakami, Yoichi; Ishihara, Sumio*; Endo, Yasuo*; Maekawa, Sadamichi*; Hirota, Kazuma*; et al.
Journal of Physics and Chemistry of Solids, 66(12), p.2157 - 2162, 2005/12
Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)We have studied electronic excitations of hole-doped manganese oxides LaSrMnO ( and ) by resonant inelastic X-ray scattering at Mn K absorption edge. We observed in the excitation spectra that the Mott gap of LaSrMnO was filled by hole-doping. In LaSrMnO, which shows a metal-insulator transition, we found that temperature dependence of scattering intensity is different between two scattering vectors. It may reflects a anisotropic electronic structure which originates from the orbital degrees of freedom in manganese oxides.
Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Maekawa, Sadamichi*; Hoesch, M.; Kuzushita, Kaori; Tsubota, Masami; Inami, Toshiya; Mizuki, Junichiro; et al.
Physical Review Letters, 94(20), p.207003_1 - 207003_4, 2005/05
Times Cited Count:72 Percentile:89.18(Physics, Multidisciplinary)We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the electron-doped high- superconductor NdCeCuO. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with -dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model.
Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Kuzushita, Kaori; Inami, Toshiya; Owada, Kenji; Maekawa, Sadamichi*; Masui, Takahiko*; Tajima, Setsuko*; et al.
Physical Review Letters, 94(18), p.187002_1 - 187002_4, 2005/05
Times Cited Count:40 Percentile:80.87(Physics, Multidisciplinary)Mott gap excitations in the optimally doped high- superconductor YBaCuO ( = 93 K) have been studied by the resonant inelastic X-ray scattering method. Anisotropic spectra in the -plane are observed in a twin-free crystal. The excitation from the one-dimensional CuO chain is enhanced at 2 eV near the zone boundary of the direction, while the excitation from the CuO plane is broad at 1.5-4 eV and almost independent of the momentum transfer. Theoretical calculation based on the one-dimensional and two-dimensional Hubbard model reproduces the observed spectra when different values of the on-site Coulomb energy are assumed. The Mott gap of the CuO chain site is found to be much smaller than that of the CuO plane site.
Ishii, Kenji; Inami, Toshiya; Owada, Kenji; Kuzushita, Kaori; Mizuki, Junichiro; Murakami, Yoichi; Ishihara, Sumio*; Endo, Yasuo*; Maekawa, Sadamichi*; Hirota, Kazuma*; et al.
Physical Review B, 70(22), p.224437_1 - 224437_6, 2004/12
Times Cited Count:19 Percentile:64.26(Materials Science, Multidisciplinary)Electronic excitations in the hole doped manganese oxides (LaSrMnO, and ) have been elucidated by using the resonant inelastic X-ray scattering (RIXS) method. A doping effect in the strongly correlated electron systems has been observed for the first time. The scattering spectra show that a salient peak appears in low energies indicating the persistence of the Mott gap. At the same time, the energy gap is partly filled by doping holes and the spectral weight energy shifts toward lower energies. The excitation spectra show little change in the momentum space as is in undoped LaMnO. On the other hand, the scattering intensities in the low energy excitations of are anisotropic in temperature dependence, which indicates an anisotropy of magnetic interaction and underlying effect of the orbital.
Nishikawa, Yunori; Usuda, Manabu; Igarashi, Junichi*
Journal of the Physical Society of Japan, 73(11), p.3171 - 3176, 2004/11
Times Cited Count:3 Percentile:26.42(Physics, Multidisciplinary)no abstracts in English
Usuda, Manabu; Igarashi, Junichi*; Kodama, Akio*
Physical Review B, 69(22), p.224402_1 - 224402_5, 2004/06
Times Cited Count:20 Percentile:65.71(Materials Science, Multidisciplinary)Magnetic resonant X-ray scattering (MRXS) at the edge of Ga in an antiferromagnetic phase of UGa is studied on the basis of a band-structure calculation. We find that a relatively large orbital polarization in the unoccupied states of the Ga band is induced by the orbital polarizations at neighboring U atoms through the Ga and U hybridization, and thereby leading to the large MRXS intensity.
Nagao, Tatsuya*; Igarashi, Junichi
Physica B; Condensed Matter, 345(1-4), p.70 - 73, 2004/03
Times Cited Count:1 Percentile:7.1(Physics, Condensed Matter)To investigate the effect of the lattice distortion on the resonant X-ray scattering (RXS) spectra in DyBC, we study the crystal electric field Hamiltonian to fit the low-lying level scheme. By using the quasi-quartet ground states of the Hamiltonian, we analyze the cooperative Jahn-Teller effect at absolute zero. We find that a certain type of buckling of sheets of B and C atoms is an energetically favored state. This naturally leads to a canted quadrupole ordering phase consistent with the experiment. We show that the obtained lattice distortion gives rise to large intensities on RXS spectra around the Dy L edge by modulating 5d bands.
Usuda, Manabu; Takahashi, Manabu*; Igarashi, Junichi
Physical Review B, 69(1), p.014408_1 - 014408_7, 2004/01
Times Cited Count:11 Percentile:49.46(Materials Science, Multidisciplinary)We have investigated the magnetic X-ray scattering spectra around the edge of Ni in antiferromagnetic NiO on the basis of an calculation. By taking account of orbital polarization through the spin-orbit interaction, we reproduce well the spectra obtained experimentally. We have analyzed the contributions of the resonant dipolar, quadrupolar, and non-resonant scattering processes and clarified the mechanism of the resonant magnetic X-ray scattering.
Ishii, Kenji; Inami, Toshiya; Murakami, Yoichi; Hao, L.*; Iwasa, Kazuaki*; Kogi, Masafumi*; Aoki, Yuji*; Sugawara, Hitoshi*; Sato, Hideyuki*; Imada, Shin*; et al.
Physica B; Condensed Matter, 329-333(1-4), p.467 - 468, 2003/05
Times Cited Count:6 Percentile:35.59(Physics, Condensed Matter)Resonant x-ray scattering study was carried out to investigate an anomalous ordered state ( = 6.5 K) in the filled skutterudite PrFeP. At the Pr- absorption edge, we observed resonant features in = odd reflections, which are forbidden in the structure above . Because these reflections contain the difference of anomalous scattering factor between two Pr atoms in the unit cell, and the ordered state is attributed to the ordering of two different electronic states of Pr.
Igarashi, Junichi; Nagao, Tatsuya*
Journal of the Physical Society of Japan, 71(7), p.1771 - 1779, 2002/07
Times Cited Count:15 Percentile:63.76(Physics, Multidisciplinary)no abstracts in English
*; *; *;
Inst. Phys. Conf. Ser., (159), p.703 - 706, 1999/00
no abstracts in English
Suzuya, Kentaro; Furusaka, Michihiro*; Watanabe, Noboru*; *; Okamura, K.*; *; Kamiyama, Tomoaki*; Suzuki, Kenji*
J. Mater. Res., 11(5), p.1169 - 1178, 1996/05
no abstracts in English