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Mori, Yuichiro*; Kagi, Hiroyuki*; Kakizawa, Sho*; Komatsu, Kazuki*; Shito, Chikara*; Iizuka, Riko*; Aoki, Katsutoshi*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; et al.
Journal of Mineralogical and Petrological Sciences, 116(6), p.309 - 313, 2021/00
Times Cited Count:0 Percentile:0.02(Mineralogy)The Earth's core is believed to contain some light elements because it is 10% less dense than pure Fe under the corresponding pressure and temperature conditions. Hydrogen, a promising candidate among light elements, has phase relations and physical properties that have been investigated mainly for the Fe-H system. This study specifically examined an Fe-Si-H system using in-situ neutron diffraction experiments to investigate the site occupancy of deuterium of hcp-FezSi hydride at 14.7 GPa and 800 K. Results of Rietveld refinement indicate hcp-FeSi hydride as having deuterium (D) occupancy of 0.24(2) exclusively at the interstitial octahedral site in the hcp lattice. The effect on the site occupancy of D by addition of 2.6 wt% Si into Fe (FeSi) was negligible compared to results obtained from an earlier study of an Fe-D system (Machida et al., 2019).
Fukada, Satoshi*; Hayashi, Takumi
Nihon Genshiryoku Gakkai-Shi, 47(9), p.623 - 629, 2005/09
no abstracts in English
Omura, Ayako; Machida, Akihiko; Watanuki, Tetsu; Aoki, Katsutoshi; Nakano, Satoshi*; Takemura, Kenichi*
Proceedings of Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (CD-ROM), 3 Pages, 2005/06
Yttrium hydride shows a structural change from a cubic dihydride to a hexagonal trihydride by hydrogenation. This is accompanied by the metal-insulator transition. The theoretical calculation of yttrium hydride speculates that the hybridization between 4d-Y and 1s-H leads to the opening of a large energy gap. They also predict that a transition from insulator to metal occurs when the volume is reduced to about 85% of the equilibrium volume in yttrium trihydride. Recently, we performed an infrared spectroscopy of yttrium trihydride to investigate pressure-induced metallization under high pressure. The insulator-metal transition occurred with an abrupt disappearance of the optical gap of 1 eV at 23 GPa. There is a possibility of the electronic transition because no structural changes occur above 20 GPa. The electronic transition can be attributed to the delocalization of the 1s electrons bound to the H+ core ions or the rearrangement of hydrogen atoms.
Tobita, Kenji; Konishi, Satoshi; Nishio, Satoshi; Kosako, Kazuaki*; Tabara, Takashi*
Purazuma, Kaku Yugo Gakkai-Shi, 77(10), p.1035 - 1039, 2001/10
no abstracts in English
Ishiyama, Shintaro; Eto, Motokuni
Material Chemistry 96: Proc. of Int. Symp. on Material Chemistry in Nuclear Environment, 0, p.595 - 607, 1996/00
no abstracts in English
; ; Shimojo, Yutaka; Morii, Yukio;
Journal of Alloys and Compounds, 231(1-2), p.755 - 759, 1995/00
Times Cited Count:14 Percentile:67.53(Chemistry, Physical)no abstracts in English
Konishi, Satoshi; Nagasaki, Takanori; Okuno, Kenji
Journal of Nuclear Materials, 223, p.294 - 299, 1995/00
Times Cited Count:101 Percentile:99.08(Materials Science, Multidisciplinary)no abstracts in English
Konishi, Satoshi; Nagasaki, Takanori; Hayashi, Takumi; Okuno, Kenji
Journal of Nuclear Materials, 223, p.300 - 304, 1995/00
Times Cited Count:22 Percentile:87.01(Materials Science, Multidisciplinary)no abstracts in English
Konishi, Satoshi; Nagasaki, Takanori; Hayashi, Takumi; Okuno, Kenji
Fusion Technology, 26(3), p.668 - 672, 1994/11
no abstracts in English
; Konishi, Satoshi; Katsuta, Hiroji; Naruse, Yuji
Fusion Technology, 9, p.506 - 509, 1986/00
no abstracts in English
Saito, Hiroyuki; Takagi, Shigeyuki*; Orimo, Shinichi*
no journal, ,
no abstracts in English
Saito, Hiroyuki; Takagi, Shigeyuki*; Iijima, Yuki*; Sato, Toyoto*; Matsuo, Motoaki*; Aoki, Katsutoshi*; Orimo, Shinichi*
no journal, ,
no abstracts in English
Saito, Hiroyuki; Takagi, Shigeyuki*; Orimo, Shinichi*; Aoki, Katsutoshi*
no journal, ,
no abstracts in English
Saito, Hiroyuki
no journal, ,
no abstracts in English
Hattori, Takanori; Nakamura, Mitsutaka; Iida, Kazuki*; Machida, Akihiko*; Sano, Asami; Machida, Shinichi*; Arima, Hiroshi*; Oshita, Hidetoshi*; Honda, Takashi*; Ikeda, Kazutaka*; et al.
no journal, ,
Recently, the high-pressure state of metal hydrides has attracted much attention due to the discovery of superhydrides with high- near room temperature under ultra-high pressure. The vibrational state of hydrogen is important to understand the origin of high and to search for materials with higher . Incoherent Inelastic Neutron Scattering (IINS) is a powerful tool to study the vibrational excitations of hydrogen. Therefore, vibrational excitations of various metal hydrides have been investigated, but a unified understanding is still lacking due to the differences in the lattice size and electronic states. Pressure allows us to investigate the nature of the lattice more rationally because the lattice size can be changed continuously. In the present work, we have developed an apparatus for IINS under high pressure, and succeeded in observing vibrational excitations of hydrogen in ZrH and TiH up to 21 GPa. In this talk, we will introduce the principle of IINS, the experiments, and the results obtained.
Endo, Naruki*; Saito, Hiroyuki; Machida, Akihiko
no journal, ,
no abstracts in English
Endo, Naruki*; Saito, Hiroyuki; Machida, Akihiko
no journal, ,
no abstracts in English
Saito, Hiroyuki
no journal, ,
no abstracts in English
Saito, Hiroyuki
no journal, ,
no abstracts in English