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Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.
Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02
Times Cited Count：52 Percentile：95.92(Chemistry, Multidisciplinary)Oikawa, Kenichi; Kawasaki, Takuro; Ohara, Takashi; Kiyanagi, Ryoji; Kaneko, Koji; Tamura, Itaru; Nakamura, Tatsuya; Harada, Masahide; Nakao, Akiko*; Hanashima, Takayasu*; et al.
JPS Conference Proceedings (Internet), 1, p.014013_1 - 014013_5, 2014/03
A new single crystal time-of-flight neutron diffractometer has been installed at BL18 of the Materials and Life Science Experimental Facility of J-PARC. The diffractometer "SENJU" was designed for precise crystal and magnetic structure analyses using a small crystal less than 1.0 mm
under multiple extreme environments such as low-temperature and high-magnetic field. The first neutron beam was delivered to the sample position on March 5, 2012. Subsequently, the hardware and software of SENJU have been checked and confirmed that they worked fine. At the same time, diffraction experiments of several organic and inorganic crystals have been done using NaCl, C12A7, and so on. In these measurements, Bragg reflections in the high-Q region (d-spacing 
0.5 
) were clearly observed and analyzed successfully. In this presentation, we will show the instrument design and performance evaluation of SENJU in detail.
O
Wakimoto, Shuichi; Kimura, Hiroyuki*; Sakamoto, Yuma*; Fukunaga, Mamoru*; Noda, Yukio*; Takeda, Masayasu; Kakurai, Kazuhisa
Physical Review B, 88(14), p.140403_1 - 140403_5, 2013/10
Times Cited Count：19 Percentile：60.82(Materials Science, Multidisciplinary)Tamura, Itaru; Oikawa, Kenichi; Kawasaki, Takuro; Ohara, Takashi; Kaneko, Koji; Kiyanagi, Ryoji; Kimura, Hiroyuki*; Takahashi, Miwako; Kiyotani, Tamiko*; Arai, Masatoshi; et al.
Journal of Physics; Conference Series, 340, p.012040_1 - 012040_4, 2012/02
Times Cited Count：10 Percentile：93.58(Physics, Condensed Matter)
O
(
= Ho, Er)Wakimoto, Shuichi; Kimura, Hiroyuki*; Fukunaga, Mamoru*; Nishihata, Keisuke*; Takeda, Masayasu; Kakurai, Kazuhisa; Noda, Yukio*; Tokura, Yoshinori*
Physica B; Condensed Matter, 404(17), p.2513 - 2516, 2009/09
Times Cited Count：5 Percentile：25.54(Physics, Condensed Matter)OFukunaga, Mamoru*; Sakamoto, Yuma*; Kimura, Hiroyuki*; Noda, Yukio*; Abe, Nobuyuki*; Taniguchi, Koji*; Arima, Takahisa*; Wakimoto, Shuichi; Takeda, Masayasu; Kakurai, Kazuhisa; et al.
Physical Review Letters, 103(7), p.077204_1 - 077204_4, 2009/08
Times Cited Count：50 Percentile：86.01(Physics, Multidisciplinary)
Sb
by single crystal neutron diffraction and maximum-entropy analysisKaneko, Koji; Metoki, Naoto; Kimura, Hiroyuki*; Noda, Yukio*; Matsuda, Tatsuma; Kogi, Masafumi*
Journal of the Physical Society of Japan, 78(7), p.074710_1 - 074710_4, 2009/07
Times Cited Count：18 Percentile：68.26(Physics, Multidisciplinary)In order to obtain a detailed picture of rattling in PrOsSb, a single crystal neutron diffraction experiment and a maximum-entropy analysis were carried out. At room temperature, a widely distributed anisotropic Pr nuclear density in the Sb icosahedron cage was revealed. An unusual trapezoidal form in the cross-sectional density profile of Pr clearly demonstrates the presence of strong anharmonicity in the Pr potential, in which the 
direction has the maximum spread. The highest density is found at an off-center position along the same direction. The Pr density distribution becomes isotropic and sharp by cooling down to 8 K. Moreover, the highest density of Pr at 8 K is found at the center of the cage. The obtained nuclear density distribution and its temperature variation indicate that the rattling in PrOsSb is a strong anharmonic thermal motion without an off-center potential minimum.
Sr
NiO
and La
(Ba,Sr)
CuO superconducting compoundsWakimoto, Shuichi; Kimura, Hiroyuki*; Ishii, Kenji; Ikeuchi, Kazuhiko; Adachi, Tadashi*; Fujita, Masaki*; Kakurai, Kazuhisa; Koike, Yoji*; Mizuki, Junichiro; Noda, Yukio*; et al.
Physical Review Letters, 102(15), p.157001_1 - 157001_4, 2009/04
Times Cited Count：25 Percentile：74.92(Physics, Multidisciplinary)OKimura, Hiroyuki*; Wakimoto, Shuichi; Fukunaga, Mamoru*; Noda, Yukio*; Kaneko, Koji; Metoki, Naoto; Kakurai, Kazuhisa; Kay, Kohn*
Journal of the Physical Society of Japan, 78(3), p.034718_1 - 034718_5, 2009/03
Times Cited Count：5 Percentile：37.14(Physics, Multidisciplinary)OKim, J.-H.*; Lee, S.-H.*; Park, S. I.*; Kenzelmann, M.*; Harris, A. B.*; Schefer, J.*; Chung, J.-H.*; Majkrzak, C. F.*; Takeda, Masayasu; Wakimoto, Shuichi; et al.
Physical Review B, 78(24), p.245115_1 - 245115_10, 2008/12
Times Cited Count：41 Percentile：80.23(Materials Science, Multidisciplinary)Fujii, Yasuhiko; Arai, Masatoshi; Kadono, Ryosuke*; Kanaya, Toshiji*; Kamiyama, Takashi*; Niimura, Nobuo*; Nojiri, Hiroyuki*; Noda, Yukio*; Yagi, Takehiko*; Yamada, Kazuyoshi*
Kotai Butsuri, 43(7), p.441 - 450, 2008/07
no abstracts in English
SbKaneko, Koji; Metoki, Naoto; Kimura, Hiroyuki*; Noda, Yukio*; Matsuda, Tatsuma; Kogi, Masafumi*
Physica B; Condensed Matter, 403(5-9), p.874 - 876, 2008/04
Times Cited Count：1 Percentile：6.29(Physics, Condensed Matter)In order to clarify the detailed structure of PrOsSb, single crystal neutron diffraction experiments were carried out and obtained data were analyzed by means of the maximum entropy method (MEM). A space- and time-averaged nuclear density distribution reflecting a thermal vibration can be obtained through the MEM analysis. The result unveils a widely spread Pr distribution in the Sb cage at room temperature. The Pr density has a almost flat distribution in the real space centered at the Sb cage, which reaches roughly 0.58 in the full width at half maximum (FWHM). These features are far from the simple harmonic model, namely, the present result suggests the strong anharmonicity of the Pr potential in the Sb cage.
O; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloomOwada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.
Hoshako, 21(2), p.87 - 96, 2008/03
Devil's flower has been found in a temperature-pressure phase diagram of NaVO, which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaVO. The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.
Kaneko, Koji; Metoki, Naoto; Kimura, Hiroyuki*; Noda, Yukio*; Matsuda, Tatsuma; Kogi, Masafumi*
Journal of the Physical Society of Japan, 77(Suppl.A), p.245 - 247, 2008/00
Times Cited Count：3 Percentile：27.56(Physics, Multidisciplinary)In filled skutterudite compounds, the importance of rattling is suggested in connection with the formation of heavy quasiparticles and superconductivity. A combination of the single crystal neutron diffraction and the maximum entropy method (MEM) offers an ability to unveil the thermal motion of Pr in PrOsSb without any specific model. The result reveals the widely spread Pr nuclear density distribution at room temperature, which has a trapezoidal shape in the real space with the width of roughly 0.6 in the full width at half maximum. In contrast, the Pr distribution at 8 K has a sharp, isotropic gaussian shape, and the highest density locates at the center of the cage. These features indicate the strong anharmonicity of the Pr potential in the Sb cage.
O under high pressure; A Synchrotron X-ray diffraction studyOwada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.
Physical Review B, 76(9), p.094113_1 - 094113_10, 2007/09
Times Cited Count：10 Percentile：44.46(Materials Science, Multidisciplinary)Structural relations between two ground states of the ANNNI (Axial Next Nearest Neighbor Ising) compound NaVO, C
- and C
-phases below and above the transition pressure 
= 1 GPa, were investigated by X-ray diffraction and scattering techniques. The structure of the C-phase is well explained by the 
(
) pattern which is one of four layers (
) of the C-phase, however, the amount of the atomic shifts under the conditions 1.6 GPa and 6 K is 27% that under ambient pressure. On the other hand, resonant X-ray scattering showed that the charges are disproportionated under high pressure. Based on these facts, it was concluded that charge disproportionation corresponds to the Ising variable in NaVO, where the atomic shifts are regarded as linearly coupled to the Ising spins. These results lead to the hypothesis that the competitive interactions between the Ising spins may result from the Ising spin-phonon coupling.
MnOKimura, Hiroyuki*; Kobayashi, Satoru*; Wakimoto, Shuichi; Noda, Yukio*; Kon, Keiichiro*
Ferroelectrics, 354, p.77 - 85, 2007/01
Times Cited Count：25 Percentile：68.32(Materials Science, Multidisciplinary)A review is given on the studies of magnetic properties and dielectric properties as functions of temperature and magnetic field for various multiferroic MnO ( = rare-earth) compounds. We have observed successive dielectric and magnetic phase transitions which concomitantly take place and a so-called multiferroics is realized. In this system, the ferroelectricity is magnetically induced and the commensurate magnetism is indispensable to produce a spontaneous electric polarization. The microscopic origin of the magnetically induced ferroelectricity and the role of the rare-earth magnetic moment for a colossal magnetoelectric effect in MnO will be discussed in the viewpoint of the magnetic structure.
OKimura, Hiroyuki*; Kamada, Yoichi*; Noda, Yukio*; Kaneko, Koji; Metoki, Naoto; Kohn, Key*
Journal of the Physical Society of Japan, 75(11), p.113701_1 - 113701_4, 2006/11
Times Cited Count：36 Percentile：80.12(Physics, Multidisciplinary)Neutron diffraction measurements under high magnetic fields in multiferroic HoMnO have revealed a clear relationship between microscopic magnetism and field-induced ferroelectricity. The applied magnetic field induces a first-order phase transition from an incommensurate magnetic order to a commensurate magnetic order, where a spontaneous electric polarization occurs. The one-to-one correspondence between the magnetic phase diagram and the dielectric phase diagram under magnetic field clearly indicates that the electric polarization is magnetically induced and the commensurate magnetic structure is indispensable to the ferroelectricity in the multiferroic 
MnO system.
m fully depleted CMOS/SOI digital logic devicesMakihara, Akiko*; Asai, Hiroaki*; Tsuchiya, Yoshihisa*; Amano, Yukio*; Midorikawa, Masahiko*; Shindo, Hiroyuki*; Kuboyama, Satoshi*; Onoda, Shinobu; Hirao, Toshio; Nakajima, Yasuhito*; et al.
Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.95 - 98, 2006/10
no abstracts in English
(Sr,Ba)CuOWakimoto, Shuichi; Kimura, Hiroyuki*; Fujita, Masaki*; Yamada, Kazuyoshi*; Noda, Yukio*; Shirane, Gen*; Gu, G.*; Kim, H.*; Birgeneau, R. J.*
Journal of the Physical Society of Japan, 75(7), p.074714_1 - 074714_6, 2006/07
Times Cited Count：23 Percentile：72.17(Physics, Multidisciplinary)We report incommensurate diffuse (ICD) scattering appearing in the high-temperature-tetragonal (HTT) phase of La(Sr,Ba)CuO with 
observed by the neutron diffraction technique. For all compositions, a sharp superlattice peak of the low-temperature-orthorhombic (LTO) structure is replaced by a pair of ICD peaks with the modulation vector parallel to the CuO
octahedral tilting direction, that is, the diagonal Cu-Cu direction of the CuO plane, above the LTO-HTT transition temperature 
. The temperature dependences of the incommensurability 
for all samples scale approximately as 
, while those of the integrated intensity of the ICD peaks scale as 
. These observations together with absence of ICD peaks in the non-superconducting 
sample evince a universal incommensurate lattice instability of hole-doped 214 cuprates in the superconducting regime.
Inami, Toshiya; Owada, Kenji; Kimura, Hiroyuki*; Watanabe, Masashi*; Noda, Yukio*; Nakamura, Hiroyuki*; Yamasaki, Tomoaki*; Shiga, Masayuki*; Ikeda, Naoshi*; Murakami, Yoichi
Physical Review B, 66(7), p.073108_1 - 073108_4, 2002/08
Times Cited Count：45 Percentile：84.68(Materials Science, Multidisciplinary)It has been believed for a long time that the metal-to-insulator (MI) transition of BaVS is not accompanied by any spatial order of spin and lattice. We have carried out x-ray diffraction measurements of BaVS single crystals using laboratory x-ray source as well as synchrotron radiation, and found that superlatiice reflections which double the lattice constant c exist below the transition temperature. The most porbable space group at the low-temperature insulator phase contains two in equivalent vanadium sites and thus a charge disproportionation of the vnadium ions is considered as the main cause of the MI transition.
