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Takeda, Yukiharu; Pospil, J.*; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori
Physical Review B, 108(8), p.085129_1 - 085129_10, 2023/08
Yamagami, Kohei*; Fujisawa, Yuita*; Pardo-Almanza, M*; Smith, B. R. M.*; Sumida, Kazuki; Takeda, Yukiharu; Okada, Yoshinori*
Physical Review B, 106(4), p.045137_1 - 045137_8, 2022/07
Times Cited Count:2 Percentile:37.1(Materials Science, Multidisciplinary)Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Pospil, J.*; Yamamoto, Etsuji; Haga, Yoshinori
Physical Review B, 105(11), p.115128_1 - 115128_6, 2022/03
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori
Electronic Structure (Internet), 3(2), p.024008_1 - 024008_8, 2021/06
Fujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*
Physical Review B, 99(3), p.035109_1 - 035109_5, 2019/01
Times Cited Count:9 Percentile:53.77(Materials Science, Multidisciplinary)Fujimori, Shinichi; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*
Progress in Nuclear Science and Technology (Internet), 5, p.82 - 85, 2018/11
Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori
Progress in Nuclear Science and Technology (Internet), 5, p.171 - 174, 2018/11
Takeda, Yukiharu; Saito, Yuji; Okane, Tetsuo; Yamagami, Hiroshi; Matsuda, Tatsuma*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika*
Physical Review B, 97(18), p.184414_1 - 184414_7, 2018/05
Times Cited Count:1 Percentile:15.79(Materials Science, Multidisciplinary)Fujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Matsumoto, Yuji*; Yamamoto, Etsuji; Tateiwa, Naoyuki; et al.
Physical Review B, 96(12), p.125117_1 - 125117_9, 2017/09
Times Cited Count:8 Percentile:43.06(Materials Science, Multidisciplinary)Fujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*
Physical Review B, 96(11), p.115126_1 - 115126_10, 2017/09
Times Cited Count:7 Percentile:35.8(Materials Science, Multidisciplinary)Fujimori, Shinichi; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika
Journal of the Physical Society of Japan, 85(6), p.062001_1 - 062001_33, 2016/06
Times Cited Count:31 Percentile:84.24(Physics, Multidisciplinary)Fujimori, Shinichi; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika
Journal of Electron Spectroscopy and Related Phenomena, 208, p.105 - 110, 2016/04
Times Cited Count:1 Percentile:8.62(Spectroscopy)Recent progresses in the soft X-ray photoelectron spectroscopy (PES) studies ( 100 eV) for uranium compounds are briefly reviewed. The soft X-ray PES has enhanced sensitivities for the bulk U 5f electronic structure, which is essential to understand the unique physical properties of uranium compounds. In particular, the recent remarkable improvement in energy resolutions from an order of 1 eV to 100 meV made it possible to observe fine structures in Uf density of states. Furthermore, soft X-ray ARPES becomes available due to the increase of photon flux at beamlines in third generation synchrotron radiation facilities. The technique made it possible to observe bulk band structures and Fermi surfaces of uranium compounds and therefore, the results can be directly compared with theoretical models such as band-structure calculations. The core-level spectra of uranium compounds show a systematic behavior depending on their electronic structures, suggesting that they can be utilized to determine basic physical parameters such as the U 5f-ligand hybridizations or Coulomb interaction between U 5f electrons. It is shown that soft X-ray PES provides unique opportunities to understand the electronic structures of uranium compounds.
Teruya, Atsushi*; Takeda, Masataka*; Nakamura, Ai*; Harima, Hisatomo*; Haga, Yoshinori; Uchima, Kiyoharu*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 84(5), p.054703_1 - 054703_15, 2015/05
Times Cited Count:4 Percentile:35.01(Physics, Multidisciplinary)Fujimori, Shinichi; Okochi, Takuo*; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; et al.
Physical Review B, 91(17), p.174503_1 - 174503_9, 2015/05
Times Cited Count:23 Percentile:70.81(Materials Science, Multidisciplinary)The electronic structures of the ferromagnetic superconductors UGe and UCoGe in the paramagnetic phase were studied by angle-resolved photoelectron spectroscopy using soft X-rays ( = 400-500 eV). The quasi-particle bands with large contributions from U 5 states were observed in the vicinity of EF, suggesting that the U 5 electrons of these compounds have an itinerant character. Their overall band structures were explained by the band-structure calculations treating all the U 5 electrons as being itinerant. Meanwhile, the states in the vicinity of EF show considerable deviations from the results of band-structure calculations, suggesting that the shapes of Fermi surface of these compounds are qualitatively different from the calculations, possibly caused by electron correlation effect in the complicated band structures of the low-symmetry crystals. Strong hybridization between U 5 and states in UCoGe were found by the 2p-3d resonant photoemission experiment, suggesting that states have finite contributions to the magnetic, transport, and superconducting properties.
Fukaya, Masaaki*; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Takeda, Yoshinori*; Miura, Norihiko*; Uyama, Masao*; Kaneda, Tsutomu*; Ueda, Tadashi*; Toda, Akiko*; et al.
JAEA-Technology 2014-040, 199 Pages, 2015/03
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) project consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies for restoration and/or reduction of the excavation damage. The researches on engineering technology such as verification of the initial design were being conducted by using data measured during construction as a part of the second phase of the MIU plan. Examination about the plug for reflood test in the GL-500m Access/Research Gallery-North as part of the development of technologies for restoration and/or reduction of excavation damage were carried out. Specifically, Literature survey was carried out about the plug, based on the result of literature survey, examination of the design condition, design of the plug and rock stability using numerical simulation, selection of materials for major parts, and grouting for water inflow from between rock and plug, were carried out in this study.
Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Yoshinori*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.
JAEA-Technology 2014-019, 495 Pages, 2014/08
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) research on engineering technology deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research is mainly aimed in this study, which is categorized in (a) development of design and construction planning technologies, (b) development of construction technologies, (c) development of countermeasure technologies, and (d) development of technologies for security. In this study, the researches on engineering technology are being conducted in these four categories by using data measured during construction as a part of the second phase of the MIU plan.
Fujimori, Shinichi; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; et al.
JPS Conference Proceedings (Internet), 3, p.011072_1 - 011072_5, 2014/06
In this presentation, we review some of our recent photoemission studies on uranium superconductors by means of soft X-ray synchrotron radiation ARPES (SX-ARPES). Results of SX-ARPES study on URhGe and UPdAl will be presented. URhGe is a ferromagnetic superconductor with = 9.5 K and = 0.26 K while UPdAl is an antiferromagnetic superconductor with = 14 K and = 1.8 K. We have revealed the three-dimensional electronic structures of those compounds by SX-ARPES, and they are compared with those calculated by LDA.
Fujimori, Shinichi; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi*; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; et al.
Physical Review B, 89(10), p.104518_1 - 104518_7, 2014/03
Times Cited Count:21 Percentile:65.37(Materials Science, Multidisciplinary)The electronic structure of the ferromagnetic superconductor URhGe in the paramagnetic phase has been studied by angle-resolved photoelectron spectroscopy using soft X rays ( = 595-700 eV). Dispersive bands with large contributions from U 5 states were observed in the ARPES spectra, and form Fermi surfaces. The band structure in the paramagnetic phase is partly explained by the band-structure calculation treating all U 5 electrons as being itinerant, suggesting that an itinerant description of U 5 states is a good starting point for this compound. On the other hand, there are qualitative disagreements especially in the band structure near the Fermi level ( 0.5 eV). The experimentally observed bands are less dispersive than the calculation, and the shape of the Fermi surface is different from the calculation. The changes in spectral functions due to the ferromagnetic transition were observed in bands near the Fermi level, suggesting that the ferromagnetism in this compound has an itinerant origin.
Takeda, Yukiharu; Saito, Yuji; Okane, Tetsuo; Yamagami, Hiroshi; Matsuda, Tatsuma*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika; Fisk, Z.
Physical Review B, 88(7), p.075108_1 - 075108_6, 2013/08
Times Cited Count:9 Percentile:43.58(Materials Science, Multidisciplinary)no abstracts in English
Yasui, Akira*; Saito, Yuji; Fujimori, Shinichi; Kawasaki, Ikuto*; Okane, Tetsuo; Takeda, Yukiharu; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma*; Haga, Yoshinori; et al.
Physical Review B, 87(7), p.075131_1 - 075131_6, 2013/02
Times Cited Count:6 Percentile:29.47(Materials Science, Multidisciplinary)We have performed soft X-ray angle-resolved photoemission spectroscopy (ARPES) measurements on YbRhSi and clarified its three-dimensional bulk valence-band structures. The ARPES spectra have not only Yb multiplet peaks but also a finite contribution of Yb peaks at 15 K, corresponding to the valence fluctuating behavior in this compound. This means that Yb 4f electrons in this compound have itinerant character below the . We have found that dispersions of the valence bands except the vicinity of the Yb 4f bands agree better with those of the band-structure calculation of LuRhSi than those of YbRhSi within a local-density approximation. In addition, the Yb 3d-4f resonant photoemission spectra of YbRhSi strongly suggest the existence of Yb 5d electrons in the valence band. We conclude that the charge transfer from the Yb 4f state to the Yb 5d state has an important role in the formation of the valence band of YbRhSi.