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Komatsu, Kazuki*; Noritake, Fumiya*; Machida, Shinichi*; Sano, Asami; Hattori, Takanori; Yamane, Ryo*; Kagi, Hiroyuki*
Scientific Reports (Internet), 6, p.28920_1 - 28920_11, 2016/07
Times Cited Count：23 Percentile：54.81(Multidisciplinary Sciences)We investigate in-situ neutron diffraction measurements and density functional theory calculations to revisit the structure and stability of ice XV. We find that none of the completely ordered configurations are particular favored; instead, partially ordered states are established as a mixture of ordered domains in disordered ice VI. This scenario in which several kinds of ordered configuration coexist dispels the contradictions in previous studies. It means that the order disorder pairs in ice polymorphs are not one-to-one correspondent pairs but rather have one-to-n correspondence, where there are possible configurations at finite temperature.
Fe(CN)
accompanied with enhanced conductivityLi, K.*; Zheng, H.*; Hattori, Takanori; Sano, Asami; Tulk, C. A.*; Molaison, J.*; Feygenson, M.*; Ivanov, I. N.*; Yang, W.*; Mao, H.-K.*
Inorganic Chemistry, 54(23), p.11276 - 11282, 2015/12
Times Cited Count：5 Percentile：25.81(Chemistry, Inorganic & Nuclear)Pressure-induced polymerization of triple bonds would produce conductive conjugated double bonds. To find a metal cyanide with a low polymerization pressure, anhydrous LiFe(CN) is synthesized and its crystal structure is determined. The irreversible bonding between the CN
can be realized by use of the industrial apparatus. The conductivity is enhanced by more than 3 orders of magnitude, which makes the polymerized LiFe(CN) a potential cathode material for rechargeable lithium batteries.
Osakabe, Toyotaka; Kato, Yoshihiro*; Honmoto, Satoru*; Kuwahara, Keitaro*
Koatsuryoku No Kagaku To Gijutsu, 25(1), p.57 - 63, 2015/03
In this article, we describe an unique technique for electrical insulation of metallic gasket to perform simultaneous measurements of electrical resistivity and neutron diffraction under high pressure. The anodic oxide coating was adopted as the insulation layer of the aluminum (JIS A2017) gasket used in the hybrid-anvil device for neutron diffraction. In the feasibility tests of the coated gaskets, maximum pressure of about 6 GPa was generated without electrical breakdown of the coating or disconnection of Au leads.
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.
Hannan, A.*; Osakabe, Toyotaka; Kogi, Masafumi*; Iwasa, Kazuaki*
Applied Physics A, 74(Suppl.1), p.S565 - S567, 2002/12
Times Cited Count：6 Percentile：28.33(Materials Science, Multidisciplinary)no abstracts in English
phase diagram and magnetic structures of CeSbOsakabe, Toyotaka; Hannan, A.*; Tachi, N.*; Kogi, Masafumi*; Kitazawa, Hideaki*
Applied Physics A, 74(Suppl.1), p.S799 - S801, 2002/12
Times Cited Count：6 Percentile：28.33(Materials Science, Multidisciplinary)no abstracts in English
Osakabe, Toyotaka
Koatsuryoku No Kagaku To Gijutsu, 11(3), p.203 - 210, 2001/00
no abstracts in English
Osakabe, Toyotaka; Kogi, Masafumi*; Iwasa, Kazuaki*; Kubota, M.*; Yoshizawa, Hideki*; Haga, Yoshinori; Suzuki, T.*
Physica B; Condensed Matter, 281-282, p.434 - 436, 2000/06
Times Cited Count：5 Percentile：32.8(Physics, Condensed Matter)no abstracts in English
Fukuda, Takeshi
Purazuma, Kaku Yugo Gakkai-Shi, 75(12), p.1377 - 1395, 1999/12
no abstracts in English
*; Moriai, Atsushi; ; *; Onodera, Akifumi*; Amita, Fujitsugu*; Katano, Susumu
Physica B; Condensed Matter, 241-243, p.145 - 147, 1998/00
Times Cited Count：1 Percentile：11.83(Physics, Condensed Matter)no abstracts in English
Urakawa, Satoru*; Igawa, Naoki; Umesaki, Norimasa*; Igarashi, Kazuo*; Shimomura, Osamu*; Ono, Hideo
High Pressure Research, 14(4-6), p.375 - 382, 1996/12
Times Cited Count：6 Percentile：53.14(Physics, Multidisciplinary)no abstracts in English
*; Ozawa, K.
Physical Review B, 18(5), p.2173 - 2178, 1978/00
Times Cited Count：104no abstracts in English
*; Ozawa, K.
Journal of Applied Physics, 48(6), p.2139 - 2144, 1977/06
Times Cited Count：16no abstracts in English
Osakabe, Toyotaka; Kato, Yoshihiro*; Kuwahara, Keitaro*
no journal, ,
no abstracts in English
Kamada, Yutaka
no journal, ,
no abstracts in English
Osakabe, Toyotaka; Kato, Yoshihiro*; Honmoto, Satoru*; Kuwahara, Keitaro*
no journal, ,
no abstracts in English
-AlOOH and investigation of symmetrization of hydrogen bondSano, Asami; Hattori, Takanori
no journal, ,
To investigate the relation between the symmetrization of hydrogen bond and change of physical properties in the hydrous mineral of the -AlOOH, we conducted neutron diffraction experiments at the high-pressure neutron diffractometer PLANET in the J-PARC. We observed the disappearance of 021 reflection at high pressure in -AlOOH which indicates the transition from the structure with asymmetric hydrogen bond (
) to that with disordered or symmetric hydrogen bond (
), in agreement with previous single crystal X-ray diffraction study. On the other hand the transition pressure is higher in -AlOOD, which was determined to be 12 GPa. The detail about the hydrogen distribution around the transition pressure and its relevance to the change of compressibility and anomalies in sound velocities will be discussed.
-AlOOHSano, Asami; Hattori, Takanori
no journal, ,
To investigate the relation of change in compression behaviours at high-pressure and hydrogen-bond symmetrization in hydrous mineral -AlOOH, we conducted high-pressure neutron diffraction experiments at the PLANET in the J-PARC. The results indicate the phase transitions occur at 8.4 GPa in -AlOOH and 12.1 GPa in -AlOOD.
P
under low temperature and high pressureHonmoto, Satoru*; Osakabe, Toyotaka; Kuwahara, Keitaro*
no journal, ,
We have carried out high-pressure neutron magnetic diffraction experiments and high-pressure transport measurements on filled skutterudite compound PrFeP under identical pressurization conditions up to 5.5 GPa. This compound shows metal-to-insulator transition at 2.4 GPa and simultaneously antiferromagnetic transition. At first, the metal-to-insulator transition is thought to be a kind of Slater transition accompanied by the antiferromagnetic transition. According to the analysis of resistivity data, we, however, found the insulator state arose from the hybridization between f-electrons of Pr ions and conduction electrons. Furthermore, the hybridization gap grows up to about 4 GPa and in reversal shrinks with increasing pressure. On the other hand, the pressure dependence of the antiferromagnetic transition temperature appears to show negative correlation to that of the gap. We can not interpret the behavior microscopically at present, but, predict that this is closely related to the Fermi surface instability of this compound.
Osakabe, Toyotaka; Kuwahara, Keitaro*; Honmoto, Satoru*; Kato, Yoshihiro*
no journal, ,
no abstracts in English
