Dec. 2012, 日本中性子科学会第１０回技術賞, iMATERIAにおける試料自動交換ロボットの開発
Japan society

Oct. 2010, The 1st Michael Meissner Prize of 6th International Workshop on Sample Environment at Neutron Scattering Facilities, Automatic sample exchange system for a large number of samples at room temperature
International society

Local noncentrosymmetric effect on antiferromagnetic ordering in the tetragonal crystal structure phase of Eu₃Ir₄Sn₁₃
Takanobu Kumada; Yotaro Suzuki; Kazuaki Iwasa; Keitaro Kuwahara; Hajime Sagayama; Hironori Nakao; Motoyuki Ishikado; Akinori Hoshikawa, Last, American Physical Society (APS)
Physical Review B, 31 Mar. 2025, [Reviewed]

Degradation of Polypropylene by Ultraviolet Light and Higher Order Structure　　　　　　　　　　　　　　　
Akinori Hoshikawa; Hidemaru Sootome, Lead
SPring-8/SACLA Research Report, Jun. 2024, [Reviewed]

中性子回折によるパーメンジュール合金の高温相変態解析　　　　　　　　　　　　　　　
佐藤李行; 河原幸汰; 富田俊郎; 星川晃範; 鈴木 茂; 佐藤成男
Ｘ線分析の進歩55, Mar. 2024, [Reviewed]

Na-ion dynamics in the solid solution Na_xCa_1−xCr₂O₄ studied by muon spin rotation and neutron diffraction
Elisabetta Nocerino; Ola Kenji Forslund; Hiroya Sakurai; Nami Matsubara; Anton Zubayer; Federico Mazza; Stephen Cottrell; Akihiro Koda; Isao Watanabe; Akinori Hoshikawa; Takashi Saito; Jun Sugiyama; Yasmine Sassa; Martin Månsson, Thermally activated Na diffusion mechanism in the honeycomb-like 1D channels of the solid solution Na_xCa_1−xCr₂O₄., Royal Society of Chemistry (RSC)
Sustainable Energy & Fuels, Feb. 2024, [Reviewed]

Competition between magnetic interactions and structural instabilities leading to itinerant frustration in the triangular lattice antiferromagnet LiCrSe2
Elisabetta Nocerino; Shintaro Kobayashi; Catherine Witteveen; Ola K. Forslund; Nami Matsubara; Chiu Tang; Takeshi Matsukawa; Akinori Hoshikawa; Akihiro Koda; Kazuyoshi Yoshimura; Izumi Umegaki; Yasmine Sassa; Fabian O. von Rohr; Vladimir Pomjakushin; Jess H. Brewer; Jun Sugiyama; Martin Månsson, Abstract

LiCrSe₂ constitutes a recent valuable addition to the ensemble of two-dimensional triangular lattice antiferromagnets. In this work, we present a comprehensive study of the low temperature nuclear and magnetic structure established in this material. Being subject to a strong magnetoelastic coupling, LiCrSe₂ was found to undergo a first order structural transition from a trigonal crystal system ($$P\bar{3}m1$$) to a monoclinic one (C2/m) at T_s = 30 K. Such restructuring of the lattice is accompanied by a magnetic transition at T_N = 30 K. Refinement of the magnetic structure with neutron diffraction data and complementary muon spin rotation analysis reveal the presence of a complex incommensurate magnetic structure with a up-up-down-down arrangement of the chromium moments with ferromagnetic double chains coupled antiferromagnetically. The spin axial vector is also modulated both in direction and modulus, resulting in a spin density wave-like order with periodic suppression of the chromium moment along the chains. This behavior is believed to appear as a result of strong competition between direct exchange antiferromagnetic and superexchange ferromagnetic couplings established between both nearest neighbor and next nearest neighbor Cr³⁺ ions. We finally conjecture that the resulting magnetic order is stabilized via subtle vacancy/charge order within the lithium layers, potentially causing a mix of two co-existing magnetic phases within the sample., Springer Science and Business Media LLC
Communications Materials, 07 Oct. 2023, [Reviewed]

Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2O4 revealed with high resolution neutron diffraction and μ+SR　　　　　　　　　　　　　　　
Elisabetta Nocerino; Ola Kenji Forslund; Hiroya Sakurai; Akinori Hoshikawa; Nami Matsubara; Daniel Andreica; Anton Zubayer; Federico Mazza; Takashi Saito; Jun Sugiyama; Izumi Umegaki; Yasmine Sassa and Martin Månsson
J. Phys. Mater., Jul. 2023, [Reviewed]

Magnetic Ordering and Structural Phase Transitions of Nd3T4Sn13 (T = Rh and Ir)　　　　　　　　　　　　　　　
Ami Shimoda; Kazuaki Iwasa; Keitaro Kuwahara; Hajime Sagayama; Hironori Nakao; Motoyuki Ishikado; Takashi Ohhara; Akiko Nakao; Akinori Hoshikawa; and Toru Ishigaki
JPS Conf. Proc., May 2023, [Reviewed]

低合金TRIP 鋼の二相域温度によるミクロ組織形成依存性の中性子回折観察　　　　　　　　　　　　　　　
河原幸汰; 梅村和希; 平野孝史; 小貫祐介; 星川晃範; 富田俊郎; 佐藤成男
Ｘ線分析の進歩54, Mar. 2023, [Reviewed]

〔Major achievements〕Observation of hydrogen bonding network in hydrogen sulfide hydrate using neutron diffraction　　　　　　　　　　　　　　　
Akinori Hoshikawa; Akihiro Hachikubo
Chem. Phys. Lett., Feb. 2023, [Reviewed]

Nuclear and magnetic spin structure of the antiferromagnetic triangular lattice compound LiCrTe2 investigated by μ+ SR, neutron and X-ray diffraction　　　　　　　　　　　　　　　
E. Nocerino; C. Witteveen; S. Kobayashi; O. K. Forslund; N. Matsubara; A. Zubayer; F. Mazza; S. Kawaguchi; A. Hoshikawa; I. Umegaki; J. Sugiyama; K. Yoshimura; Y. Sassa; F. O. von Rohr & M. Månsson
Scientific reports, Dec. 2022, [Reviewed]

Crystal Structures and Conduction Paths of Sc-doped CaTiO3 Fast Oxide-ion Conductors with Orthorhombic Symmetry
Katsuhiro Nomura; Shin-ichi Hashimoto; Tomoaki Namioka; Hiroaki Kato; Takeshi Hagiwara; Akinori Hoshikawa, American Chemical Society (ACS)
Inorg. Chem., Oct. 2022, [Reviewed]

〔Major achievements〕Structural changes due to the ordered guest molecules in deuterated ethane hydrate　　　　　　　　　　　　　　　
Akinori Hoshikawa
Chem. Phys. Lett., Aug. 2022, [Reviewed]

Direct Observation of Nucleus of Lithium in a C60 Fullerene Cage by Neutron Diffraction Study　　　　　　　　　　　　　　　
E. Kwon; T. Matsukawa; A. Hoshikawa; T. Ishigaki; S. Aoyagi; K. Kawachi; Y. Kasama
Chem. Phys. Lett., Aug. 2022, [Reviewed]

Crystal Structure of Hydrogen Sulfide Hydrate　　　　　　　　　　　　　　　
Takashi Mochiku; Akinori Hoshikawa; Akihiro Hachikubo; Yoshio Katsuya; Masahiko Tanaka; Shigeki Konishi; Osami Sakata
SPring-8/SACLA利用研究成果集, Apr. 2022, [Reviewed]

中性子回折測定によるRietveld 解析を用いた低合金TRIP 鋼の相変態観察　　　　　　　　　　　　　　　
梅村和希; 小貫祐介; 星川晃範; 富田俊郎; 田中泰明; 藤原知哉; 諏訪嘉宏; 河野佳織; 佐藤成男, 日本分析化学会
X線分析の進歩53, Mar. 2022, [Reviewed]

Texture Memory in Si-Mn and ODS Steels Observed In Situ by Pulsed Neutron and Synchrotron X-Ray Diffractions and Prediction by Double Kurdjumov-Sachs Relation: A Concept for Intense Variant Selection　　　　　　　　　　　　　　　
Toshiro Tomida; Elena Vakhitova; Denis Sornin; Jonathan Wright; Manuel François; Yusuke Onuki; Takashi Hirano; Akinori Hoshikawa; Toru Ishigaki; Shigeo Sato
Metallurgical and Materials Transactions A, Apr. 2021, [Reviewed]

〔Major achievements〕Automatic Sample Changer for In-situ Observation during Charging and Discharging Process of Battery　　　　　　　　　　　　　　　
Akinori Hoshikawa; Toru Ishigaki
JPS Conf. Proc., Mar. 2021, [Reviewed]

Rietveld texture解析を用いた鉄鋼ミクロ組織評価における等方性温度因子の影響　　　　　　　　　　　　　　　
平野 孝史; 小貫 祐介; 星川 晃範; 富田 俊郎; 佐藤 成男, アグネ技術センター
X線分析の進歩 51, Mar. 2020, [Reviewed]

Tetragonality induced superconductivity in anti-ThCr2 Si2-type RE2 O2 Bi (RE= rare earth) with Bi square nets
Ryosuke Sei; Hideyuki Kawasoko; Kota Matsumoto; Masato Arimitsu; Kyohei Terakado; Daichi Oka; Shintaro Fukuda; Noriaki Kimura; Hidetaka Kasai; Eiji Nishibori; Kenji Ohoyama; Akinori Hoshikawa; Toru Ishigaki; Tetsuya Hasegawa; Tomoteru Fukumura,

Superconductivity in RE₂O₂Bi was universally governed by unit cell tetragonality c/a, irrespective of the usually destructive long-range magnetic ordering.

, Royal Society of Chemistry (RSC)
Dalton Transactions, Mar. 2020, [Reviewed]

In Situ Observation of Bainite Transformation and Simultaneous Carbon Enrichment in Austenite in Low-Alloyed TRIP Steel Using Time-of-Flight Neutron Diffraction Techniques　　　　　　　　　　　　　　　
Y Onuki; T Hirano; A Hoshikawa; S Sato; T Tomida
Metall. Mat. Trans. A, Nov. 2019, [Reviewed]

Composition-driven structural variation in ferrielectric phase of (Bi1/2Na1/2) TiO3-Ba (Mg1/3Nb2/3) O3
Y. Kitanaka; K. Makisumi; Y. Noguchi; M. Miyayama; A. Hoshikawa; T. Ishigaki, IOP Publishing
J. J. Appl. Phys., Nov. 2019, [Reviewed]

Investigation of magnetism and magnetic structure of anti-ThCr2Si2-type Tb2O2Bi by magnetization and neutron diffraction measurements
Hideyuki Kawasoko; Kenji Ohoyama; Ryosuke Sei; Kota Matsumoto; Daichi Oka; Akinori Hoshikawa; Toru Ishigaki; Tomoteru Fukumura
AIP Advances, Nov. 2019, [Reviewed]

Analysis of reverse transformation behavior in iron-based alloys based on quantitative microstructure information by neutron diffraction　　　　　　　　　　　　　　　
Kenta Hanawa; Yusuke Onuki; Yuta Uemura; Akinori Hoshikawa; Shigeru Suzuki; Hiroaki Otsuka; Yuya Chiba; Shigeo Sato
J. Iron Steel. Inst. Jpn., Oct. 2019, [Reviewed]

〔Major achievements〕Evaluation of filling rate of methane in methane-propane hydrate by neutron powder diffraction　　　　　　　　　　　　　　　
Akinori Hoshikawa; Takeshi Matsukawa; Toru Ishigaki
Physica B, Dec. 2018, [Reviewed]

Z-MEM, Maximum Entropy Method software for electron/nuclear density distribution in Z-Code
Yoshihisa Ishikawa; Junrong Zhang; Ryoji Kiyanagi; Masao Yonemura; Takeshi Matsukawa; Akinori Hoshikawa; Toru Ishigaki; Shuki Torii; Ryoko Oishi-Tomiyasu; Takashi Kamiyama, Maximum Entropy Method (MEM) is one of powerful tools for material science. We developed the program Z-MEM for evaluation of electron and nuclear density distribution by MEM analysis and Fourier synthesis. This code is designed by the multi-threading library OpenMP, so that the calculation performance is significantly improvements for MEM analysis. Z-MEM is bundled in Z-Rietveld, which is Rietveld software for X-ray and neutron powder diffraction, via the application programming interface (API). Since Z-MEM have equipped with the graphical user interface operations, users can perform from Rietveld refinement to MEM analysis seamlessly.
Physica B, Dec. 2018, [Reviewed]

Local Disorder in Proton Conductor BaSn0. 5In0. 5O2.75 Analyzed by Neutron Diffraction/Atomic Pair Distribution Function　　　　　　　　　　　　　　　
Naoki Igawa; Katsuaki Kodama; Tomitsugu Taguchi; Yukihiko Yoshida; Takeshi Matsukawa; Akinori Hoshikawa; Toru Ishigaki
Trans. Mater. Res. Soc. Jpn., Dec. 2018, [Reviewed]

Crystal structure and ferroelectric polarization of tetragonal (Bi1/2Na1/2) TiO3-12BaTiO3　　　　　　　　　　　　　　　
Yuuki Kitanaka; Motohiro Ogino; Yuji Noguchi; Masaru Miyayama; Akinori Hoshikawa; Toru Ishigaki
J. J. Appl. Phys., Oct. 2018, [Reviewed]

Neutron Diffraction Studies on Valence Ordering Compound YbPd
Kohei Oyama; Masaki Sugishima; Kousuke Tanabe; Akihiro Mitsuda; Hirofumi Wada; Kenji Ohoyama; Takeshi Matsukawa; Yukihiko Yoshida; Akinori Hoshikawa; Toru Ishigaki; Kazuaki Iwasa, © 2018 The Physical Society of Japan. The magnetic structure of YbPd was determined for a newly synthesized strain-free sample by neutron diffraction techniques. The sinusoidal magnetic structure characterized by an incommensurate wave vector k = (0.080 0 0.32) is observed in the magnetic-ordered phase between T3 = 1.9 K and T4 = 0.5 K, which is composed of the magneticmoment amplitude of 0.3 μB parallel to the a-axis in the tetragonal crystal-structure phase. The modulated magnetic structure is consistent with the previously proposed Yb-ion valence ordered structure appearing below T2 = 105 K, which consists of the periodic arrangement of magnetic and nonmagnetic Yb ions.
J. Phys. Soc. Jpn., Oct. 2018, [Reviewed]

Temperature-induced structural transition of ceria by bulk reduction under hydrogen atmosphere　　　　　　　　　　　　　　　
T. Matsukawa; A. Hoshikawa; T. Ishigaki
CrystEngComm, Aug. 2018, [Reviewed]

Large entropy change derived from orbitally assisted three-centered two-electron bond formation in metallic Li0.33VS2
N Katayama; S Tamura; T Yamaguchi; K Sugimoto; K Iida; T Matsukawa; A Hoshikawa; T Ishigaki; S Kobayashi; Y Ohta; H Sawa, American Physical Society (APS)
Phys. Rev. B, Aug. 2018, [Reviewed]

Strain-Induced Martensitic Transformation and Texture Evolution in Cold-Rolled Co-Cr Alloys　　　　　　　　　　　　　　　
Yusuke Onuki; Shigeo Sato; Maiko Nakagawa; Kenta Yamanaka; Manami Mori; Akinori Hoshikawa; Toru Ishigaki; Akihiko Chiba
Quantum Beam Sci., Jun. 2018, [Reviewed]

Development and verification of simultaneous measurement system for texture and phase fraction by time-of-flight neutron diffraction at iMATERIA　　　　　　　　　　　　　　　
Y Onuki; A Hoshikawa; S Sato; S Nishino; T Ishigaki; T Tomida
IOP Conf. Ser.: Mater. Sci. Eng., Jun. 2018, [Reviewed]

Rietveld Texture Analysis for Metals Having Hexagonal Close-Packed Phase by Using Time-of-Flight Neutron Diffraction at iMATERIA
Yusuke Onuki; Akinori Hoshikawa; Soichiro Nishino; Shigeo Sato; Toru Ishigaki
Adv. Eng. Mater., Apr. 2018, [Reviewed]

Mesoscopic Investigation of an “Immiscible” Cyclohexane and Water Micro-mixture in Carbon Micropores by Contrast Variation Small-angle Neutron Scattering　　　　　　　　　　　　　　　
Masatsugu Yoshimoto; Yukihiko Yoshida; Yohei Noda; Satoshi Koizumi; Shinichi Takata; Junichi Suzuki; Akinori Hoshikawa; Toru Ishigaki; Sumio Ozeki; and Taku Iiyama
Chem. Lett., Jan. 2018, [Reviewed]

Crystal structure of blue-colored ceria during redox reactions in a hydrogen atmosphere
Takeshi Matsukawa; Akinori Hoshikawa; Eiki Niwa; Masatomo Yashima and Toru Ishigaki, © 2018 The Royal Society of Chemistry. Neutron diffraction measurements revealed that the oxyhydroxide ceria CeO2Hy(0 ≦ y ≦1) was formed by the interaction of hydrogen under high temperature. Ceria was kinetically reduced in hydrogen depending on the isothermal holding time, and the crystal phase of CeO2H was precipitated during the short isothermal holding time.
CrystEngComm, Jan. 2018, [Reviewed]

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments
Kenji Nakajima; Yukinobu Kawakita; Shinichi Itoh; Jun Abe; Kazuya Aizawa; Hiroyuki Aoki; Hitoshi Endo; Masaki Fujita; Kenichi Funakoshi; Wu Gong; Masahide Harada; Stefanus Harjo; Takanori Hattori; Masahiro Hino; Takashi Honda; Akinori Hoshikawa; Kazutaka Ikeda; Takashi Ino; Toru Ishigaki; Yoshihisa Ishikawa; Hiroki Iwase; Tetsuya Kai; Ryoichi Kajimoto; Takashi Kamiyama; Naokatsu Kaneko; Daichi Kawana; Seiko Ohira-Kawamura; Takuro Kawasaki; Atsushi Kimura; Ryoji Kiyanagi; Kenji Kojima; Katsuhiro Kusaka; Sanghyun Lee; Shinichi Machida; Takatsugu Masuda; Kenji Mishima; Koji Mitamura; Mitsutaka Nakamura; Shoji Nakamura; Akiko Nakao; Tatsuro Oda; Takashi Ohhara; Kazuki Ohishi; Hidetoshi Ohshita; Kenichi Oikawa; Toshiya Otomo; Asami Sano-Furukawa; Kaoru Shibata; Takenao Shinohara; Kazuhiko Soyama; Jun-ichi Suzuki; Kentaro Suzuya; Atsushi Takahara; Shin-ichi Takata; Masayasu Takeda; Yosuke Toh; Shuki Torii; Naoya Torikai; Norifumi L. Yamada; Taro Yamada; Dai Yamazaki; Tetsuya Yokoo; Masao Yonemura and Hideki Yoshizawa, The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned., MDPI
Quantum Beam Sci., Dec. 2017, [Reviewed]

TOF型パルス中性子回折を用いた金属ミクロ組織解析
佐藤 成男、小貫 祐介、星川 晃範、中川 真惟子、山中 謙太、富田 俊郎, アグネ技術センター
金属, Nov. 2017, [Reviewed]

Quantitative phase fraction analysis of steel combined with texture analysis using timeof-flight neutron diffraction　　　　　　　　　　　　　　　
Yusuke Onuki; Akinori Hoshikawa; Shigeo Sato; Toru Ishigaki; Toshiro Tomida
J. Phys. Soc. Jpn., Oct. 2017, [Reviewed]

Time-of-Flight Elastic and Inelastic Neutron Scattering Studies on the Localized 4d Electron Layered Perovskite La5Mo4O16
Kazuki Iida; Ryoichi Kajimoto; Yusuke Mizuno; Kazuya Kamazawa; Yasuhiro Inamura; Akinori Hoshikawa; Yukihiko Yoshida; Takeshi Matsukawa; Toru Ishigaki; Yukihiko Kawamura; Soshi Ibuka; Tetsuya Yokoo5; Shinichi Itoh; and Takuro Katsufuji, The magnetic structure and spin-wave excitations in the quasi-square-lattice layered perovskite compound La5Mo4O16 were studied by a combination of neutron diffraction and inelastic neutron scattering techniques using polycrystalline sample. Neutron powder diffraction refinement revealed that the magnetic structure is ferrimagnetic in the ab plane with antiferromagnetic stacking along the c-axis where the magnetic propagation vector is k = (0, 0, 1/2). The ordered magnetic moments are estimated to be 0.54(2)mu(B) for Mo5+ (4d(1)) ions and 1.07(3)mu(B) for Mo4+ (4d(2)) ions at 4K, which are about half of the expected values. The inelastic neutron scattering results display strong easy-axis magnetic anisotropy along the c-axis due to the spin-orbit interaction in Mo ions evidenced by the spin gap at the magnetic zone center. The model Hamiltonian consisting of in-plane anisotropic exchange interactions, the interlayer exchange interaction, and easy-axis single-ion anisotropy can explain our inelastic neutron scattering data well. Strong Ising-like anisotropy and weak interlayer coupling compared with the intralayer exchange interaction can explain both the high-temperature magnetoresistance and long-time magnetization decay recently observed in La5Mo4O16., PHYSICAL SOC JAPAN
J. Phys. Soc. Jpn., May 2017, [Reviewed]

Unusually Stable Plastic Crystal Phase of CCl4 Confined in Graphitic Slit-shaped Micropores from Neutron Diffraction
Masatsugu Yoshimoto; Ryusuke Futamura; Akinori Hoshikawa; Toru Ishigaki; Taro Uchida; and Taku Iiyama,

Structural changes with temperature of CCl₄ confined in a 1.1 nm slit-shaped carbon nanospace were investigated by neutron diffraction (ND) measurements and radial distribution function f_drdf analyses. Bulk CCl₄ exhibits a plastic crystal (PC) phase between 225.5 and 250 K. In the confined space, although clear phase transition points cannot be determined, f_drdf suggests that the PC phase extends to temperatures as low as 160 K. The smooth surface of the activated carbon assists the rotational motion of CCl₄.

, The Chemical Society of Japan
Chem. Lett., Apr. 2017, [Reviewed]

Evaluation of hydrogen-bonding distance in organic nonlinear optical crystals for high-output terahertz-wave generation
Takeshi Matsukawa; Akinori Hoshikawa; Yoshihisa Ishikawa; Toru Ishigaki, The crystal structure of deuterated 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST-d(26)) was obtained by powder X-ray and neutron diffraction measurements. The scattering length density distributions of deuterium atoms were successfully obtained from neutron diffraction data using the maximum-entropy method. From the density distributions, we estimated the hydrogen-bonding distances, which contribute significantly to the vibrational modes of DAST at 1 THz. Inhibition of these hydrogen bonds could allow the development of new nonlinear optical materials with low THz absorption. (C) 2017 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
J. Mol. Struct., Apr. 2017, [Reviewed]

マクロ・ミクロスケール集合組織測定を併用したAZ31マグネシウム合金の室温変形機構の検討　　　　　　　　　　　　　　　
小貫祐介、星川晃範、佐藤成男、石垣徹, 一般社団法人 軽金属学会
軽金属, Nov. 2016, [Reviewed]

Rapid Measurement of Texture of Metals by Time-of-Flight Neutron Diffraction at iMATERIA and its Applications
Y. Onuki; A. Hoshikawa; S. Sato; T. Ishigaki
Materials Science Forum, Nov. 2016, [Reviewed]

Rapid measurement scheme for texture in cubic metallic materials using time-of-flight neutron diffraction at iMATERIA
Y. Onuki; A. Hoshikawa; Shigeo Sato; Pingguang Xu; Toru Ishigaki; Yoichi Saito; Hidekazu Todoroki and Makoto Hayashi, A rapid texture measurement system has been developed on the time-of-flight neutron diffractometer iMATERIA (beamline BL20, MLF/J-PARC, Japan). Quantitative Rietveld texture analysis with a neutron beam exposure of several minutes without sample rotation was investigated using a duplex stainless steel, and the minimum number of diffraction spectra required for the analysis was determined experimentally. The rapid measurement scheme employs 132 spectra, and by this scheme the quantitative determination of volume fractions of texture components in ferrite and austenite cubic phases in a duplex stainless steel can be made in a short time. This quantitative and rapid measurement scheme is based on the salient features of iMATERIA as a powder diffractometer, i.e. a fairly high resolution in d spacing and numerous detectors covering a wide range of scattering angle.
J. Appl. Cryst., Oct. 2016, [Reviewed]

Temperature Dependence of Crystal Structure and THz Absorption Spectra of Organic Nonlinear Optical Stilbazolium Material for High-Output THz-Wave Generation　　　　　　　　　　　　　　　
Takeshi Matsukawa; Hiromichi Hoshina; Akinori Hoshikawa; Chiko Otani; Toru Ishigaki
J. Infrared Milli Terahz Waves, Jun. 2016, [Reviewed]

Deformation mechanism of AZ31 magnesium alloy at room temperature studied by macro and micro texture measurements
Yusuke Onuki; Akinori Hoshikawa; Shigeo Sato; Toru Ishigaki, The authors measured texture change during uniaxial tensile deformation of extruded bar of AZ31 magnesium alloy by time-of-flight neutron diffraction and EBSD (electron backscatter diffraction). Texture measurement by neutron diffraction revealed the transition of tensile axis distribution in overall gauge volume during the deformation. The concentration of the tensile axis initially observed at≤ 2130≥. With increasing strain, the dominant peak appeared at≤ 9 1 10 0≥ and the initial peak weakened. It was also found that the total density of≤ hki0≥ decreased during the deformation. EBSD showed activations of {101 1} compression twinning and following double twinning. The twinned region were oriented away from the≤ hki0≥ orientation group. The amount of twinning gradually increased with increasing strain. On the other hand, the deformation of the matrix was achieved by slip deformation, resulting in the formation of the peak at ≤9 1 10 0≥. Based on the above results, it was concluded that the reason for poor ductility of magnesium alloys may not be a lack of≤ c+a≥ slip but twinning and deformation concentration inside of the twins., Japan Institute of Light Metals
Keikinzoku/Journal of Japan Institute of Light Metals, 2016

20pPSB-30 Powder neutron diffraction of valence ordering compound YbPd
Oyama K.; Mitsuda A.; Ohoyama K.; Matsukawa T.; Yoshida Y.; Hoshikawa A.; Ishigaki T.; Iwasa K.; Wada H., The Physical Society of Japan (JPS)
Meeting Abstracts of the Physical Society of Japan, 2016

Forge-Hardened TiZr Null-Matrix Alloy for Neutron Scattering under Extreme Conditions　　　　　　　　　　　　　　　
Takuo Okuchi; Akinori Hoshikawa and Toru Ishigaki
Metals, Dec. 2015, [Reviewed]

〔Major achievements〕Structure Analysis of Propane Hydrates　　　　　　　　　　　　　　　
Akinori Hoshikawa; Yukihiko Yoshida; Takeshi Matsukawa; and Toru Ishigaki
JPS Conf. Proc., Sep. 2015, [Reviewed]

Crystal Structure of the Fe1-xSr2YCu2+xO6+δ Magnetic Superconductor　　　　　　　　　　　　　　　
Takashi Mochiku; Yoshiaki; Hata; Akinori Hoshikawa; Toru Ishigaki; Hiroshi Yasuoka; and Kazuto Hirata
JPS Conf. Proc., Sep. 2015, [Reviewed]

Local Lattice Distortion Caused by Short-range Charge Ordering in Transition Metal Oxides
Katsuaki Kodama; Naoki Igawa; Shin-ichi Shamoto; Kazutaka Ikeda; Hidetoshi Ohshita; Naokatsu Kaneko; Toshiya Otomo; Kentaro Suzuya; Akinori Hoshikawa; and Toru Ishigaki, Cubic spinel compound LiMn$_2$O$_4$ with the mixed valence of Mn$^{3.5+}$ has non-metallic conductivity. The local structure determined by the PDF analysis has an orthorhombic lattice distortion and includes inequivalent Mn$^{3+}$ and Mn$^{4+}$ sites. YBaCo$_2$O$_5$ also exhibits non-metallic conductivity although the Co has the mixed valence of +2.5 above 220 K which corresponds with charge ordering temperature. The PDF obtained at 450 K is not reproduced by the PDF calculated for the averaged structure and can be reproduced by the PDF calculated for the structure model corresponding to the charge ordering state. These results suggest that the valence electrons are localized with short-range periodicity, resulting in the non-metallic conductivities in these materials.
JPS Conf. Proc., Sep. 2015, [Reviewed]

Synthesis and transport properties of ternary type-I Si clathrate K8Al7Si39　　　　　　　　　　　　　　　
S. K. Singh; T. Mochiku; S. Ibuka; Y. Isoda; A. Hoshikawa; T. Ishigaki and M. Imai
Jpn. J. Appl. Phys., Aug. 2015, [Reviewed]

Neutron crystal structure analysis of stilbazolium derivatives for terahertz-wave generation　　　　　　　　　　　　　　　
T. Matsukawa; Y. Yoshida; A. Hoshikawa; S. Okada; and T. Ishigaki
CrystEngComm, Apr. 2015, [Reviewed]

Identification of Various Coexisting Phases in Superconducting and Non-superconducting Samples of RbxFe2-ySe2　　　　　　　　　　　　　　　
Y. Kobayashi; S. Kototani; K. Ohishi; M. Itoh; A. Hoshikawa; T. Ishigaki; and M. Sato
J. Phys. Soc. Jpn., Mar. 2015, [Reviewed]

21aPS-107 ハニカム格子を形成するスピン系Li_3Ni_2AO_6 (A=Sb, Bi)の磁気ダイナミクスと磁気構造
福井 皓人; 安井 幸夫; 星川 晃範; 石垣 徹; 井川 直樹, 一般社団法人日本物理学会
日本物理学会講演概要集, 2015

New O2/P2-type Li-Excess Layered Manganese Oxides as Promising Multi-Functional Electrode Materials for Rechargeable Li/Na Batteries　　　　　　　　　　　　　　　
Naoaki Yabuuchi; Ryo Hara; Masataka Kajiyama; Kei Kubota; Toru Ishigaki; Akinori Hoshikawa and Shinichi Komaba
Adv. Energy Mater., Sep. 2014, [Reviewed]

Neutron diffraction studies on structural effect for Ni-doping in LiCo1-xNixO2
Dyah S. Adipranotoa; Toru Ishigaki; Akinori Hoshikawa; Kenji Iwase; Masao Yonemura; Kazuhiro Mori; Takashi Kamiyama; Yukio Morii; Makoto Hayashi, We report structural effect for Ni-doping in lithium cobalt oxide (LiCoO2) studied by the time-of-flight (TOF) neutron powder diffractions measured at RT. Crystal and local structures of LiCo1 - xNiO2 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) powders, that were prepared by the solid-state reaction methods, have been respectively examined by using the IBARAKI Neutron Design Diffractometer (iMATERIA) of JPARC and Nanoscale-Ordered Material Diffractometer (NOMAD) of ORNL. The Rietveld refinement for neutron diffraction data of LiCo1 - xNixO2 that all have been indexed to the rhombohedral system with trigonal symmetry in the space group R-3m, revealed the lattice parameter c/a ratio that tends to the ideal value as decreasing Ni-contents, while the atomic pair distribution function (PDF) analysis for neutron data of LiCo1-xNixO2 revealed that the Co-O and the Ni-O pair correlation lengths under the first peak of G(r) that respectively vary from 1.88 to 1.9 angstrom and from 1.98 to 2.0 angstrom, with average Ni-O correlation length (1.99 angstrom) seems to be slightly larger than average Co-O correlation length (1.89 angstrom). Rather than that resulted by the Rietveld analysis, the PDF analysis suggested that the diffusion pathways between Co-O in the LiCo(1 - x)Ni(x)O2 system remain stable at similar to 1.89 angstrom for all Ni-contents. (C) 2013 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Solid State Ion., Sep. 2014, [Reviewed]

Slow dynamics in the geometrically frustrated magnet ZnFe2O4: Universal features of aging phenomena in spin glasses　　　　　　　　　　　　　　　
H. Mamiya; N. Tsujii; N. Terada; S. Nimori; H. Kitazawa; A. Hoshikawa; and T. Ishigaki
Phys. Rev. B, Jul. 2014, [Reviewed]

Local Structural Analysis by using Atomic Pair Distribution Function on Mixed Valence Compound LiMn2O4
Katsuaki Kodama; Naoki Igawa; Shin-ichi Shamoto; Kazutaka Ikeda; Hidetoshi Ohshita; Naokatsu Kaneko; Toshiya Otomo; Kentaro Suzuya; Akinori Hoshikawa and Toru Ishigaki, LiMn$_2$O$_4$ has a cubic spinel structure with a single Mn site whose valence is +3.5. Below about 260 K, the compound exhibits a charge ordering and has inequivalent Mn sites with valences of +3 and +4. However, even in the cubic phase without the charge ordering, temperature dependence of the electrical conductivity is non-metallic. We have performed PDF (atomic pair distribution function) analysis on powder neutron diffraction data of LiMn$_2$O$_4$ obtained above 300 K where the compound has cubic structure. The local structure determined by PDF analysis has an orthorhombic lattice distortion and includes the inequivalent Mn sites with valences of +3 and +4 up to, at least, about 450 K. These results indicate that valence electrons are localized at Mn sites with short range periodicity, resulting in the non-metallic electrical conductivity. It can be regarded as a glass state of valence electrons whereas a charge ordering can be regarded as a crystallization of valence electrons.
JPS Conf. Proc., Jun. 2014, [Reviewed]

New Perovskite-Related Structure Family of Oxide-Ion Conducting Materials NdBaInO4　　　　　　　　　　　　　　　
Kotaro Fujii; Yuichi Esaki; Kazuki Omoto; Masatomo Yashima; Akinori Hoshikawa; Toru Ishigaki; and James R. Hester
Chem. Mater., Apr. 2014, [Reviewed]

Spin State of Co3+ in LaCo1-xRhxO3 Investigated by Structural Phenomena
Shinichiro Asai; Ryuji Okazaki; Ichiro Terasaki; Yukio Yasui; Wataru Kobayashi; Akiko Nakao; Kensuke Kobayashi; Reiji Kumai; Hironori Nakao; Youichi Murakami; Naoki Igawa; Akinori Hoshikawa; Toru Ishigaki; Outi Parkkima; Maarit Karppinen; Hisao Yamauchi, Neutron diffraction for a polycrystalline sample of LaCo 0:8Rh0:2O3 and synchrotron x-ray diffraction for polycrystalline samples of LaCo0:9RhO and LaCo RhO3 have been carried out in order to investigate the structural properties related with the spin state of Co3+ ions. We have found that the Co(Rh)-O bond lengths in the Co(Rh)O6 octahedron of LaCo0:8Rh0:2O3 are nearly identical at 10K. The lattice volume for the Rh3+ substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO3from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin-state and low-spinstate Co 3+ ions, and suggest that there are thermally excited high-spin-state Co3+ ions in addition to those pinned by the substituted Rh 3+ ions. © 2013 The Physical Society of Japan.
J. Phys. Soc. Jpn., Nov. 2013, [Reviewed]

A Comparative Study of LiCoO2 Polymorphs: Structural and Electrochemical Characterization of O2-, O3-, and O4-type Phases　　　　　　　　　　　　　　　
Naoaki Yabuuchi; Yuta Kawamoto; Ryo Hara; Toru Ishigaki; Akinori Hoshikawa; Masao Yonemura; Takashi Kamiyama; Shinichi Komaba
Inorg. Chem., Jul. 2013, [Reviewed]

Annealing effect on structure and superconductivity in FeSr2YCu2O6+δ magnetic superconductor　　　　　　　　　　　　　　　
T.Mochiku; Y.Hata; K.Yamaguchi; Y.Tsuchiya; A.Hoshikawa; K.Iwase; D.Sulistyanintyas; T.Ishigaki; H.Yasuoka; K.Hirata
Physics Procedia, Jan. 2013, [Reviewed]

Structure Determination of Hydrogen-bonding Network of Water in Hydrophobic Nanospace by Neutron and X-ray Diffractions　　　　　　　　　　　　　　　
Taku Iiyama; Fumika Fujisaki; Ryusuke Futamura; Atom Hamasaki; Sumio Ozeki; Akinori Hoshikawa; Toru Ishigaki
Chem. Lett., Oct. 2012, [Reviewed]

Crystal structure of GdNi3 with superlattice alloy and its hydrogen absorption-desorption property
Kenji Iwase; Kazuhiro Mori; Akinori Hoshikawa; Toru Ishigaki
International Journal of Hydrogen Energy, Oct. 2012, [Reviewed]

Crystal and Local Structure of Lithium Cobalt Oxide Studied by Neutron Diffraction　　　　　　　　　　　　　　　
Dyah S. Adipranoto; Toru Ishigaki; Akinori Hoshikawa; Kenji Wase; Hidetoshi Oguro; Masao Yonemura; Kazuhiro Mori; Takashi Kamiyama
Solid State Ion.:Ionics for Sustainable World - Proceedings of the 13th Asian Conference., Jul. 2012, [Reviewed]

Application of matrix decomposition algorithms for singular matrices to the Pawley method in Z-Rietveld
R. Oishi-Tomiyasu; M. Yonemura; T. Morishima; A. Hoshikawa; S. Torii; T. Ishigaki and T. Kamiyama
J. Appl. Cryst., Apr. 2012, [Reviewed]

Hydrogenation and structural properties of Gd2Ni7 with superlattice structure
Kenji Iwase; Kazuhiro Mori; Akinori Hoshikawa; Toru Ishigaki
International Journal of Hydrogen Energy, Mar. 2012, [Reviewed]

Neutron diffraction study on the Xe behavior in clathrate hydrate analyzed by Rietveld/maximum entropy method
N. Igawa; T. Taguchi; A. Hoshikawa; H Yamauchi; A Birumachi and Y Ishii
IOP Conf. Ser.: Mater. Sci. Eng., Oct. 2011, [Reviewed]

Synthesis of New Compound Gd5Ni19 with a Superlattice Structure and Hydrogen Absorption Properties
Kenji Iwase; Kazuhiro Mori; Akinori Hoshikawa; and Toru Ishigaki
Inorg. Chem., Oct. 2011, [Reviewed]

Structural and Magnetic Properties of Dilute Spinel Ferrites: Neutron Diffractometry and Magnetometry Investigations　　　　　　　　　　　　　　　
H. Mamiya; N. Terada; H. Kitazawa; A. Hoshikawa; T. Ishigaki
Journal of Magnetics, Jun. 2011, [Reviewed]

Three-Dimensional Strain Model for Various Kinds of Nb3Sn Wires
H. Oguro; S. Awaji; K. Watanabe; G. Nishijima; T. Ishigaki; A. Hoshikawa; K. Iwase; M. Yonemura; D.S. Adipranoto
IEEE Transactions on Applied Superconductivity, Jun. 2011, [Reviewed]

Change in Crystal Structure of LiNi0.8Co0.19Cu0.01O2 Cathode during Charge of Coin Cell Observed by Ex Situ Time-of-flight Neutron Diffraction　　　　　　　　　　　　　　　
Yasushi Idemoto; Yuta Tsukada; Naoto Kitamura; Akinori Hoshikawa; Toru Ishigaki
Chem. Lett., Jan. 2011, [Reviewed]

〔Major achievements〕Automatic sample changer for IBARAKI materials design diffractometer (iMATERIA)　　　　　　　　　　　　　　　
Akinori Hoshikawa; Toru Ishigaki; Masao Yonemura; Kenji Iwase; Hidetoshi Oguro; Dyah Sulistyanintyas; Takashi Kamiyama; Makoto Hayashi
J. Phys. Conf. Ser., Dec. 2010, [Reviewed]

Low temperature structure of FeSr2YCu2O6+d magnetic superconductor
T. Mochiku; Y. Hata; T. Wuernisha; N. Igawa; A. Hoshikawa; T. Ishigaki; H. Yasuoka; K. Hirata, FeSr2YCu2O6+delta with the tetragonal Ba2YCu3O6+delta-type structure exhibits superconductivity around 60 K, when it is properly annealed in N-2 and subsequently in O-2. This compound also exhibits antiferromagnetic order of Fe around 20 K. We have performed neutron powder diffraction of the FeSr2YCu2O6+delta system at low temperature to investigate the relation between the crystal structure and the physical properties. Neutron diffraction study indicates that this compound does not have the structure phase transition due to the tilt of the FeO6 octahedron differently from the RuSr2GdCu2O8 magnetic superconductor with the same structure, and that the magnetic order in FeSr2YCu2O6+delta is not long-range order, because we can observe no extra reflection due to the crystal and magnetic superstructure. (C) 2009 Published by Elsevier B.V., ELSEVIER SCIENCE BV
Physica C, Dec. 2010, [Reviewed]

On execution of Pawley method without requiring intensity constraints on overlapping reflections　　　　　　　　　　　　　　　
R.Oishi-Tomiyasu; M. Yonemura; A. Hoshikawa; S.Torii; T. Ishigaki; T. Kamiyama
Acta Cryst., Sep. 2010, [Reviewed]

CO2 motion in carbon dioxide deuterohydrate determined by applying maximum entropy method to neutron powder diffraction data
N. Igawa; T. Taguchi; A. Hoshikawa; Hiroshi Fukazawa; Hiroki Yamauchi; Wataru Utsumi; Yoshinobu Ishii
J. Phys. Chem. Solid., Jun. 2010, [Reviewed]

Effect of intervening structure between CuO2 sheets in heavily Fe-substituted high-Tc superconductor FeSr2YCu2O6+d　　　　　　　　　　　　　　　
T.Mochiku; Y.Hata; T.Wuernisha; Y.Matsushita; Y.Katsuya; S.Ishimaru; M.Tanaka; K.Kobayashi; A.Hoshikawa; T. Ishigaki; H. Yasuoka; K. Hirata
Physica C, Oct. 2009, [Reviewed]

Substitution effect in FeSr2YCu2O6+δ magnetic superconductor　　　　　　　　　　　　　　　
Takashi Mochiku; Tuerxun Wuernisha; Yoshiaki Hata; Akinori Hoshikawa; Hijiri Kito; Hiroshi Yasuoka; Kazuto Hirata
J. Phys. Conf. Ser., Mar. 2009, [Reviewed]

Existence of ferroelectric ice on planets-A neutron diffraction study　　　　　　　　　　　　　　　
Hiroshi Fukazawa; Akinori Hoshikawa; Bryan C. Chakoumakos; Jaime A. Fernandez-Baca
Nucl. Instr. Meth. Phys. Res. A, Feb. 2009, [Reviewed]

Rietveld analysis software for J-PARC
R. Oishi; M.Yonemura; Y.Nishimaki; S.Torii; A.Hoshikawa; T.Ishigaki; T.Morishima; K. Mori; T.Kamiyama, A new analysis software suite, Z-Code, is under development for powder diffraction data analyses in the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). This software suite comprises data processing, data analyses, graphical user interface and visualization software. As a part of Z-Code, a Rietveld analysis program for neutron (TOF and angle dispersive) and X-ray data, Z-Rietveld, has been developed. Here we report the basic traits and some significant features of Z-Rietveld. (C) 2008 Published by Elsevier B.V., ELSEVIER SCIENCE BV
Nucl. Instr. Meth. Phys. Res. A, Feb. 2009, [Reviewed]

IBARAKI materials design diffractometer (iMATERIA)-Versatileneutron diffractometer at J-PARC
T.Ishigaki; A.Hoshikawa; M.Yonemura; T.Morishima; T.Kamiyama; R.Oishi; K.Aizawa; T.Sakuma; Y.Tomota; M.Arai; M.Hayashi; K.Ebata; Y.Takano; K.Komatsuzaki; H.Asano; Y.Takano; T.Kasao, Ibaraki prefecture, the local government of the area for J-PARC site, was decided to build a versatile neutron diffractometer (IBARAKI Materials Design Diffractometer, iMATERIA) to promote an industrial application for neutron beam in J-PARC. iMATERIA is planned to be a high throughput diffractometer so that materials engineers and scientists can use it like the chemical analytical instruments in their materials development process. It covers in d range 0.18 < d (<(A)over bar>) < 5 with triangle d/d=0.16% at high resolution bank, and covers 5<d ((A) over bar)<800 with gradually changing resolution at three detector bank (90 degrees, low angle and small angle). Typical measuring time to obtain a 'Rietveld-quality' data is several minutes with the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutron but have not been familiar with neutron diffraction. The analysis software is also very important for powder diffraction, we will also prepare a software package consisting of combination of several powder-diffraction software, structural databases and visualization. The construction of iMATERIA will be completed in the end of April 2008, as one of day-one instruments for J-PARC. (c) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Nucl. Instr. Meth. Phys. Res. A, Feb. 2009, [Reviewed]

〔Major achievements〕Development of an automatic sample changer for iMATERIA
A.Hoshikawa; T.Ishigaki; M.Nagai; Y.Kobayashi; H.Sagehashi; T.Kamiyama; M.Yonemura; K. Aizawa; T.Sakuma; Y.Tomota; M.Arai; M.Hayashi; K.Ebata; Y.Takano; T.Kasao, The IBARAKI Materials Design Diffractometer (iMATERIA) is a high-throughput neutron powder diffractometer. Samples must be placed in the vacuum chamber, which is surrounded by a shield. To reduce the exchange time, an automatic sample changer must be developed that can move through both the shield and vacuum chamber. Here, we report on the current status of development of this automatic sample changer. (c) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Nucl. Instr. Meth. Phys. Res. A, Feb. 2009, [Reviewed]

Ferroelectric distortion and electronic structure in Bi4Ti3O12　　　　　　　　　　　　　　　
Yuji Noguchi; Takashi Goto; Masaru Miyayama; Akinori Hoshikawa; Takashi Kamiyama
J. Electroceram, Dec. 2008, [Reviewed]

Cation disorder and superconductivity in the Fe-based copper oxide FeSr2Y1-xNdxCu2O6+d　　　　　　　　　　　　　　　
T. Wuernisha; T. Mochiku; Y. Hata; A. Hoshikawa; H. Fujii; H. Yasuoka; H. Kitazawa
Physica C, Sep. 2008, [Reviewed]

Neutron diffraction study of Nd-substituted FeSr2YCu2O6+d magnetic superconductor　　　　　　　　　　　　　　　
T. Mochiku; T. Wuernisha; Y. Hata; A. Hoshikawa; H. Fujii; H. Yasuoka; K. Hirata
Physica C, Sep. 2008, [Reviewed]

Neutron diffraction studies of the magnetic ordering in the spinel oxide system MgxCo1-xCrxFe2-xO4
S.M. Yunus; H. Yamauchi; A.K.M. Zakaria; N. Igawa; A. Hoshikawa; Yoshinori Haga and Yoshinobu Ishii, Neutron diffraction studies were performed on the spinel oxide system MgCo1-xCrxFe2-xO4 (x = 0.0, 0.25, 0.50, 0.75 and 1.0) as a function of temperature. Presence of magnetic long-range order at low temperatures was confirmed from the evolution of Bragg reflections with the decrease of temperature. Magnetic structural properties were determined from the Rietveld analysis of neutron diffraction data recorded in the temperature range 10-810K. Sublattice and net magnetic moments for various compositions at various temperatures were found out from the analysis. The transition temperatures were also determined for all the compositions. A decreasing ferrimagnetic order with increasing substitution was revealed from the decreasing ordered sublattice moments. Huge diffuse signals around the 111 Bragg diffraction line were observed in the neutron patterns of the composition x = 1.0 below the Curie temperature indicating the existence of magnetic spin clusters. Hysteresis and low field dc magnetization measurements were done on the compositions x = 0.75 and 1.0. Thermo-magnetic irreversibility in the zero-field cooled and field cooled magnetization together with a shallow transition below Curie temperature was also observed. The various observations suggest a canted ferrimagnetic ordering in the composition range x <= 0.75 and a semi-spin glass like behavior at x = 1.0. A super-paramagnetic behavior below the paramagnetic state is also suggestive from the observed features. @ 2007 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
J. Alloys and Comp., May 2008, [Reviewed]

Cation distribution and crystallographic characterization of the quaternary spinel system MgxCo1-xCrxFe2-xO4
S.M. Yunus; H. Yamauchi; A.K.M. Zakaria; N. Igawa; A. Hoshikawa; Yoshinobu Ishii
J. Alloys and Comp., Apr. 2008, [Reviewed]

〔Major achievements〕In situ observation of CH4 hydrate growth by neutron powder diffraction　　　　　　　　　　　　　　　
A. Hoshikawa; H. Fukazawa; N. Igawa; H. Yamauchi; Y. Ishi and T. Ishigaki
Acta Cryst., Jan. 2008, [Reviewed]

Versatile IBARAKI materials design neutron diffractometer at J-PARC
T. Ishigaki; A. Hoshikawa; M. Yonemura; T. Kamiyama; S. Harjo; K. Aizawa; T. Sakuma; Y. Tomota; Y. Morii; M. Arai; M. Hayashi; K. Ebata; Y. Takano; T. Kasao, Ibaraki prefecture, the local government of the area for J-PARC site, has decided to build a versatile powder diffractometer (IBARAKI Materials Design Diffractometer) to promote industrial applications for neutron beams in J-PARC. This diffractometer is designed to be a high throughput one enabling materials scientists to use it like the chemical analytical instruments in their material development processes. It covers in d range 0.18 < d (Å) < 5 with Δd/d = 0.16% at the high resolution scattering detector bank, and covers 5 < d (Å) < 800 with gradually changing resolution. Typical measuring time to obtain a 'Rietveld-quality' data is several minutes for the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutrons but have not been familiar with neutron diffraction. © by Oldenbourg Wissenschaftsverlag.
Zeitschrift fur Kristallographie, Supplement, 01 Dec. 2007

Neutron Diffraction Study on the Defect Structure of Ta-Substituted Zn2TiO4 Oxide Ion Conductors　　　　　　　　　　　　　　　
Sigeomi Takai; Takayuki Shinohara; Akinori Hoshikawa; Stefanus Harjo; Kenichi Oikawa; Toru Ishigaki; Takashi Kamiyama and Takao Esaka
J. Ceramic Soc. Jpn., Nov. 2007, [Reviewed]

Investigation of the Oxide Ion Conduction Mechanism in LaGaO3-Based Electrolytes through High-Temperature Neutron Powder Diffraction　　　　　　　　　　　　　　　
M. Kajitani; M. Matsuda; A. Hoshikawa; T. Kamiyama; F. Izumi; M. Miyake
Key Eng. Mat., Oct. 2007, [Reviewed]

Doping effect on crystal structure and conduction property of fast oxide ion conductor LaGaO3-based perovskite　　　　　　　　　　　　　　　
M. Kajitani; M. Matsuda; A. Hoshikawa; S. Harjo; T. Kamiyama; T. Ishigaki; F. Izumi; M. Miyake
J. Phys. Chem. Solid., May 2007, [Reviewed]

Magnetic structural characterization of Mg-Co-Cr ferrite by neutron diffraction
S.M. Yunus; Hiroki Yamauchi; A.K.M. Zakaria; Naoki Igawa; Akinori Hoshikawa and Yoshinobu Ishii, Temperature- dependent neutron diffraction studies were done on the spinel oxide system MgxCo1-xCrxFe2-xO4 ( x = 0.0, 0.25, 0.50, 0.75 and 1.0). Neutron diffraction data recorded in the temperature range 10 - 810K were analyzed in the Rietveld method. Ordered sublattice magnetic moments of the five compositions of the spinel series at various temperatures were deduced from the analysis. A decreasing ordered moment with increasing substitution ( x) was found indicating a gradual weakening of ferrimagnetic order. Huge diffuse signals around the 1 1 1 Bragg diffraction peak were found in the neutron patterns of the composition x 1.0 below the Curie temperature manifesting a build- up of short- range magnetic spin clusters. The observed features suggest a canted ferrimagnetic structure in the composition range x <= 0.75 and a semi- spin glass- like transition at x 1.0. (c) 2006 Elsevier B. V. All rights reserved., ELSEVIER SCIENCE BV
J. Mag. Mag. Mat., Mar. 2007, [Reviewed]

Correlation Of The Superconductivity With The Multi‐Stack Structure In MgB2‐Type Superconductor CaAlSi
Hajime Sagayama; Yusuke Wakabayashi; Hiroshi Sawa; Takashi Kamiyama; Akinori Hoshikawa; Stefanus Harjo; Kentaro Uosato; Ajay K. Ghosh; Masashi Tokunaga; and Tsuyoshi Tamegai, CaAlSi is a superconductor with the AlB2-like structure. In this system, there are two types of multi-stack structures along c-axis, 5-fold structure and 6-fold structure. The 5-fold structure sample and the 6-fold structure sample have T-C of 6 K and 8 K, respectively. To investigate the correlation of stack structure with the superconductivity, we determined the crystal structures accurately using synchrotron radiation X-ray diffraction and neutron diffraction measured at KEK. Al and Si atoms form slightly corrugated honeycomb layers and those are ordered in both stack structures. The difference of stacking structure is caused by phase relation among Al-Si layers., AMER INST PHYSICS
AIP Conf. Proc., Dec. 2006, [Reviewed]

Erratum to "Structural change in a series of protonated layered perovskite compounds, HLnTiO4 (Ln=La, Nd and Y)". [J. Solid State Chem. 179 (2006) 1892-1897] (DOI:10.1016/j.jssc.2006.03.015)
Shunsuke Nishimoto; Motohide Matsuda; Stefanus Harjo; Akinori Hoshikawa; Takashi Kamiyama; Toru Ishigaki; Michihiro Miyake
Journal of Solid State Chemistry, Nov. 2006, [Reviewed]

Multiferroic Behavior and Two dimensitonal Magnetism of Hexagonal Manganites　　　　　　　　　　　　　　　
Seongsu Lee; Misun Kang; Changhee Lee; A. Hoshikawa; M. Yonemura; T. Kamiyama; J.-G. Park
Physica B, Nov. 2006, [Reviewed]

Structure Phase Transition in FeSr2YCu2O6+δ Superconductor
Tkashi Mochiku; Yoshiaki Hata; Kenji Iwase; Masao Yonemura; Stefanus Harjo; Akinori Hoshikawa; Kenichi Oikawa; Toru Ishigaki; Takashi Kamiyama; Hiroki Fujii; Fujio Izumi; Kazuo Kadowaki; Kazuto Hirata, FeSr(2)yCu(2)O(6+delta) exhibits superconductivity around 50K, when it is property annealed in N-2 atmosphere and subsequently in O-2 atmosphere, although as-synthesized FeSr2YCu2O6+delta does not exhibit superconductivity. To understand the effect of annealing on superconductivity, we have performed in-situ high-temperature neutron powder diffraction measurements in N-2 atmosphere. We have found that the N-2 annealing at 650 degrees C promoted the atomic ordering of Cu and Fe and that the phase transition occurred from tetragonal structure to orthorhombic superstructure at 750 degrees C. The atomic ordering of Cu and Fe did not change at all during the following annealing process. Consequently, this compound exhibits superconductivity by supplying the carrier onto the CuO2 sheet. (c) 2006 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Physica B, Nov. 2006, [Reviewed]

Deuteron ordering in ice containing impurities: a neutron diffraction study
Hiroshi Fukazawa; Akinori Hoshikawa; Hiroki Yamauchi; Yasuo Yamaguchi; Yoshinobu Ishii
Physica B, Nov. 2006, [Reviewed]

Neutron diffraction study on protonated and hydrated layered perovskite
Shunsuke Nishimoto; Motohide Matsuda; Stefanus Harjo; Akinori Hoshikawa; Takashi Kamiyama; Toru Ishigaki and Michihiro Miyake, A layered perovskite compound with Na+, D3O+ ions (H3O+) and D2O molecules (H2O) in the interlayer, DxNa1-xLaTiO4·yD 2O, has been prepared by an ion-exchange/intercalation reaction with dilute DCl solution, using an n = 1 Ruddlesden-Popper phase, NaLaTiO4. Its structure has been analyzed in order to clarify the interlayer structure by Rietveld method, using powder neutron diffraction data. The structure analysis revealed that the layered structure changed from the space group P4/nmm-I4/mmm after the ion-exchange/intercalation reaction, and it induced the transformation of perovskite layers from staggered to an eclipsed configuration. The D2O molecules and D3O+ ions loaded in the interlayer statistically occupied the sites around a body center position of rectangular space surrounded by eight apical O atoms of TiO6 octahedra in upper and lower layers. © 2006 Elsevier Inc. All rights reserved.
J. Solid State Chem., Nov. 2006, [Reviewed]

Existence of Ferroelectric Ice in the Universe
H. Fukazawa; A. Hoshikawa; Y. Ishii; B. C. Chakoumakos; J. A. Fernandez-Baca, The question as to whether or not ferroelectric ice, named ice XI, exists in a stable low-temperature phase attracts much interest. This question arose as a condensed-matter issue and became of interest in astronomy (e.g., does ice XI exist on Pluto?) because astronomical observations identified the existence of crystalline ice in our solar system. From neutron diffraction experiments, we found the temperature conditions for the transformation of the largest fraction of ice into ice XI using the lowest level of impurity dopant. The finding of bulk crystal of ordered structure firmly supports that ice XI is stable. This suggests the existence of naturally occurring ice XI at a narrow temperature range (57-66 K) in our solar system., UNIV CHICAGO PRESS
ApJ., Nov. 2006, [Reviewed]

〔Major achievements〕Neutron Powder Diffraction Study of Methane Hydrate by the Rietveld Refinement and Maximum Entropy Method
Akinori Hoshikawa; Naoki Igawa; Hiroki Yamauchi; Yoshinobu Ishii, A neutron powder diffraction study was carried out to clarify the crystal structure of deuterated methane hydrate (CD4 (.) nD(2)O, n >= 5.75). The diffraction data were analyzed by both the Rietveld method and the maximum entropy method (MEM). The structure analysis showed that only small cage had some vacancies of CD4. This result was in agreement with a Langmuir isotherm. In addition, the density distribution by MEM indicated that the D atoms of CD4 were localized in the large cage and that the C atom was located at off-center of the large cage. (c) 2006 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Physica B, Nov. 2006, [Reviewed]

〔Major achievements〕Observation of hydrogen in deuterated methane hydrate by maximum entropy method with neutron powder diffraction
Akinori Hoshikawa; Naoki Igawa; Hiroki Yamauchi; Yoshinobu Ishii, The crystal structure of deuterated methane hydrate (structure I, space group: Pm (3) over barn) was investigated by neutron powder diffraction at temperatures of 7.7-185 K. The scattering amplitude density distribution was examined by a combination of Rietveld method and maximum entropy method (MEM). The distribution of the D atoms in both D2O and CD4 molecules was clarified from three-dimensional graphic images of the scattering amplitude density. The MEM results showed that there were low-density sites for the D atom of D2O in a particular location within the D2O cage at low temperatures. The MEM provided more reasonable results because of the decrease in the R factor that is attainable by this method. Accordingly, the low-density sites for the D atom of D2O probably exist within the D2O cage. This suggests that a spatial disorder of the D atom of D2O occurs at these sites and that hydrogen bonds between D2O molecules become partially weakened. With regard to the CD4 molecules, there were high-density sites for the D atom of CD4, and the density distribution of the C and D atoms was observed separately in the scattering amplitude density image. Consequently, the C-D bonds of CD4 were not observed clearly because the CD4 molecules had an orientational disorder. The D atoms of CD4 were displaced from the line between the C and O atoms, and were located near the face center of the polygon in the cage. Accordingly, the D atoms of CD4 were not bonded to specific O atoms. This result is consistent with the hydrophobicity of the CD4 molecule. We also report the difference between the small and the large cages in the density distribution map and the temperature dependence of the scattering amplitude density. (c) 2006 American Institute of Physics., AMER INST PHYSICS
J. Chem. Phys., Jul. 2006, [Reviewed]

Two Types of Multistack Structures in MgB2-Type Superconductor CaAlSi　　　　　　　　　　　　　　　
Hajime Sagayama; Yusuke Wakabayashi; Hiroshi Sawa; Takashi Kamiyama; Akinori Hoshikawa; Stefanus Harjo; Kentaro Uozato; Ajay K. Ghosh; Masashi Tokunaga and Tsuyoshi Tamegai
J. Phys. Soc. Jpn., Apr. 2006, [Reviewed]

Doping effect on crystal structure of fast oxide ion conductor LaGaO 3-based perovskite compounds
Masahiro Kajitani; Motohide Matsuda; Akinori Hoshikawa; Takashi Kamiyama; Fujio Izumi; Michihiro Miyake, Doping effects of Sr and/or Mg on the crystal structures of LaGaO 3 perovskites were investigated. The doping with Mg into Ga-site in LaGaO3 led to structural change from the orthorhombic primitive lattice (Pbnm) to the orthorhombic body-centered lattice (Ibmm) at room temperature. The orthorhombic cell (Ibmm) of LaGa0.9Mg 0.1O2.95 changed to the monoclinic (I2/a) by doping with Sr into La site. Neutron powder diffraction analyses revealed that these compounds had GaO6 octahedral tilt. The GaO6 octahedral tilt angles were reduced with doping with Sr and/or Mg.
Key Engineering Materials, 2006, [Reviewed]

Structural change in a series of protonated layered perovskite compounds, HLnTiO4 (Ln=La, Nd and Y)　　　　　　　　　　　　　　　
S. Nishimoto; M. Matsuda; S. Harjo; A. Hoshikawa; Takashi Kamiyama; Toru Ishigaki and Michihiro Miyake
J. Solid State Chem, Jan. 2006, [Reviewed]

Structure determination of n=1 Ruddlesden Popper compound HLaTiO4 by powder neutron diffraction　　　　　　　　　　　　　　　
S. Nishimoto; M. Matsuda; S. Harjo; A. Hoshikawa; Takashi Kamiyama; Toru Ishigaki and Michihiro Miyake
J. Eur. Ceramic Soc., Jan. 2006, [Reviewed]

〔Major achievements〕Neutron powder diffraction study of methane deuterohydrate by the maximum entropy method
Akinori Hoshikawa; Naoki Igawa; Hiroki Yamauchi; Yoshinobu Ishii, To examine the nature of thermal motions of the CH4 molecules in the methane deuterohydrate (8CH(4)center dot 46D(2)O), the scattering length density distribution was observed by the maximum entropy method (MEM) using neutron powder diffraction data measured in the temperature range of 7-185 K. We drew the scattering-length density distribution as three dimensional graphic images and used the same isosurface level for all temperatures. The negative scattering length density, corresponding to the H atoms of CH4, was observed only in the large cage. The positive scattering length density attributed to the C atom of CH4 was observed at the center of each cage. With an increase in temperature, the negative and positive scattering length densities in the large cage disappear. The positive scattering length density remains at the center of the small cage regardless of temperature. These results strongly indicate that the motions of CH4 depend on the cage size and geometry. (c) 2005 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
J. Phys. Chem. Solid., Oct. 2005, [Reviewed]

In Situ Neutron Diffraction Study on Fast Oxide Ion Conductor LaGaO3-Based Perovskite Compounds　　　　　　　　　　　　　　　
Masahiro Kajitani; Motohide Matsuda; Akinori Hoshikawa; Stefanus Harjo; Takashi Kamiyama; Toru Ishigaki; Fujio Izumi; and Michihiro Miyake
Chem. Mater., Aug. 2005, [Reviewed]

Formation and growth of ice XI: A powder neutron diffraction study
Hiroshi Fukazawa; Akinori Hoshikawa; Hiroki Yamauchi; Yasuo Yamaguchi; Yoshinobu Ishii, We measured neutron diffraction profiles of powdered KOD-doped D2O ice to investigate the formation and growth of ice XI, a deuterium-ordered phase of ice, from ice Ih, a disordered phase. During the measurements, the ice was annealed at 57 K for about 17 h, and then warmed up and kept at 68 K for about 55 h. which are below the transition temperature T-c = 76 K. The diffraction profiles for the doped ice at 57 K did not change with time and were close to those for ice Ih with the deuterium-disordered arrangement. However, when the temperature increased from 57 to 68 K, the diffraction profiles changed, We carried out the Rietveld analysis with the parameters for a two-phase model to obtain the structural evidence of the appearance and the growth of ice XI. The analysis provided evidence of ice XI as space group Cmc2(I) at 68 K. The temporal increase of the mass fraction of ice XI showed that nucleation of ice XI began just after warming up to 68 K. Then, ice XI grew for several days in the doped ice. This study provides first structural observations of the growth of ice XI. (c) 2005 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
J. Crystal Growth, Aug. 2005, [Reviewed]

Direct observation of a coupling between spin, lattice and electric dipole moment in multiferroic YMnO3　　　　　　　　　　　　　　　
S. Lee; A. Pirogov; J. H. Han; J.-G. Park; A. Hoshikawa; and T. Kamiyama
Phys. Rev. B, May 2005, [Reviewed]

Time-Of-Flight Neutron Powder Diffraction Studies on a Chiral Two-Dimensional Molecule-Based Magnet
Akinori Hoshikawa; Takashi Kamiyama; Agus Purwanto; Kazuki Ohishi; Wataru Higemoto; Toru Ishigaki; Hiroyuki Imai; Katsuya Inoue, The magnetic structure of a chiral molecule-based magnet, [Cr(CN)(6)][Mn(S)-pnH(H2O)](H2O), has been studied using neutron powder diffraction as a function of temperature in the range from 4 K to 300 K. The 020 and 022 magnetic reflections were clearly observed below T-c = 38 K. On the basis of the intensity analysis of magnetic reflections, it was concluded that the magnetic structure is noncollinear ferrimagnetic with the magnetic (Shubnikov) space group P2(1)2'(1)2'(1) and magnetic moments of Cr and Mn atoms are mutually antiparallel along a direction near the a-axis. Our findings imply that the long-period magnetic structure, if exists, is not a helical structure but a conical one., PHYSICAL SOC JAPAN
J. Phys. Soc. Jpn., Oct. 2004, [Reviewed]

Neutron diffraction and IR spectroscopy on mechanically alloyed La-substituted PbWO4　　　　　　　　　　　　　　　
Shigeomi Takai; Tomohoro Nakanishi; Kenichi Oikawa; Shuki Torii; Akinori Hoshikawa; Takashi Kamiyama and Takao Esaka
Solid State Ion., May 2004, [Reviewed]

Structure Phase Transition in FeSr₂YCu₂O_6+d Superconductor
Mochiku Takashi; Harjo Stefanus; Hoshikawa Akinori; Oikawa Kenichi; Ishigaki Toru; Kamiyama Takashi; Kadowaki Kazuo; Hirata Kazuto, FeSr₂YCu₂O_6+δは、CuO₂面を持つ高温超伝導体の類縁化合物であるが、単に大気中で合成されただけでは超伝導は発現されない。まず窒素雰囲気で、続いて酸素雰囲気でアニールすることにより、はじめて50 K程度の超伝導体となる。このアニール過程を通して、CuとFeのc軸方向の秩序配列が促進され、続いて酸素アニールにより還元されたFeO_δ面上の酸素が補填される。しかしながら、上記の秩序配列とは異なる秩序配列を示す回折が観測され、超伝導化との関連が示唆されたため、高温その場中性子回折によって、アニール過程に沿って結晶構造解析を行い、これらの構造を検討した。, The Ceramic Society of Japan
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2004

Crystal structure analysis of -tricalcium phosphate Ca3(PO4)2 by neutron powder diffraction　　　　　　　　　　　　　　　
Masatomo Yashima; Atsushi Sakai; Takashi Kamiyama and Akinori Hoshikawa
J. Solid State Chem., Nov. 2003, [Reviewed]

Neutron Diffraction Study on Lanthanum Gallate Perovskite Compound Series　　　　　　　　　　　　　　　
Masahiro Kajitani; Motohide Matsuda; Akinori Hoshikawa; Ken-ichi Oikawa; Shunki Torii; Takashi Kamiyama; Fujio Izumi; and Michihiro Miyake
Chem. Mater., Sep. 2003, [Reviewed]

High-temperature phase transition in lanthanum titanate perovskite La0.64(Ti0.92,Nb0.08)O3　　　　　　　　　　　　　　　
Masatomo Yashima; Mizuki Mori; Takashi Kamiyama; Ken-ichi Oikawa; Akinori Hoshikawa; Shuki Torii; Koh Saitoh and Kenji Tsuda
Chem. Phys. Lett., Jun. 2003, [Reviewed]

Electrical transport in the spin-density-wave phase of (TMTSF-d(12))(2)ClO4
A Hoshikawa; T Terazaki; N Matsunaga; K Nomura; M Watanabe; S Nakatsuji; J Yamada, We have investigated the electrical transport properties in both (TMTSF)(2)ClO4 and deuterated (TMTSF-d(12))(2)ClO4. In (TMTSF-d(12))(2)ClO4, we observed the anion ordering at T-AO = 27 K with a resistance drop as well as (TMTSF)(2)ClO4, where TAO = 24 K. When the sample is quenched rapidly, the highest T-SDW is obtained as 6 and 5 K in (TMTSF)(2)ClO4 and (TMTSF-d(12))(2)ClO4, respectively. This difference indicates that the two-dimensionality of the electronic band in (TMTSF-d(12))(2)ClO4 is stronger than that in (TMTSF)(2)ClO4. We also observed the nonlinear electric conductivity with the threshold electric field E-T associated with the sliding of spin-density-wave (SDW) in (TMTSF-d(12))(2)ClO4. The value of E-T sharply increases with decreasing temperature just below T-SDW and becomes almost constant around 0.6T(SDW), In addition, E-T shows another increase below 0.4T(SDW). In (TMTSF)(2)ClO4, E-T is monotonically decreases with decreasing temperature and the temperature dependence becomes weaker as T-SDW decreases. These behaviors are attributed to the difference of the mechanism of SDW sliding between two compounds. (C) 2002 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2003, [Reviewed]

〔Major achievements〕Non-linear electric conduction in the SDW phase of (TMTSF)2NO3
A. Hoshikawa; T. Terazaki; K. Nomura; M. Tokumoto and J. M. Fabre, The non-linear electric conduction with the threshold electric field E-T was investigated by the four-wire method in the Spin-Density-Wave phase of (TMTSF)(2)NO3. The temperature dependence of E-T shows a peak around 0.3T(SDW) (T-SDW = 9.6 K), although E-T decreases with decreasing temperature below T-SDW. This anomaly around 0.3(SDW) indicates the change of electrical transport of SDW. We discuss this anomaly from the viewpoint of the multiphase of SDW phase., ELSEVIER SCIENCE SA
Synth. Met., Mar. 2001, [Reviewed]

Collective mode of spin-density-wave in (TMTSF)(2)ClO4
A Hoshikawa; K Nomura; S Takasaki; J Yamada; S Nakatsuji; H Anzai; M Tokumoto; N Kinoshita, The conductivity measurements were performed in the spin-density-wave (SDW) phase of (TMTSF)(2)ClO4. The electric conductivity increases above the clear threshold electric field E-T. The normalized excess electric conductivity [sigma(2E(T)) - sigma(0)]/sigma(0) rapidly decreases below about T* similar or equal to 0.3T(SDW), where T-SDW is the SDW transition temperature. In high electric fields far above E-T, the temperature independent electric conduction expressed as the function j = j(0) exp(-E-0/E) is observed below T*. It is suggested that the sliding of SDW with the quantum origin occurs in the low temperature. These phenomena are related to the phase transition dividing the SDW phase into two sub-phases in (TMTSF)(2)ClO4. The electric conductivity in the low temperature sub-phase is discussed in term of the SDW with the discommensuration., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, May 2000, [Reviewed]

〔Major achievements〕Collective Mode of Spin-Density-Wave in (TMTSF)2ClO4
Akinori HOSHIKAWA; Kazushige NOMURA; Satoshi TAKASAKI; Jun-ichi YAMADA; Shin’ichi NAKATSUJI; Hiroyuki ANZAI; Madoka TOKUMOTO and Nobumori KINOSHITA, The conductivity measurements were performed in the spin-density-wave (SDW) phase of (TMTSF)(2)ClO4. The electric conductivity increases above the clear threshold electric field E-T. The normalized excess electric conductivity [sigma(2E(T)) - sigma(0)]/sigma(0) rapidly decreases below about T* similar or equal to 0.3T(SDW), where T-SDW is the SDW transition temperature. In high electric fields far above E-T, the temperature independent electric conduction expressed as the function j = j(0) exp(-E-0/E) is observed below T*. It is suggested that the sliding of SDW with the quantum origin occurs in the low temperature. These phenomena are related to the phase transition dividing the SDW phase into two sub-phases in (TMTSF)(2)ClO4. The electric conductivity in the low temperature sub-phase is discussed in term of the SDW with the discommensuration., PHYSICAL SOC JAPAN
J. Phys. Soc. Jpn., May 2000, [Reviewed]

〔Major achievements〕Depinning of Spin-Density-Wave in (TMTSF)2ClO4
Akinori HOSHIKAWA; Kazushige NOMURA; Satoshi TAKASAKI; Jun-ichi YAMADA; Shin’ichi NAKATSUJI; Hiroyuki ANZAI; Madoka TOKUMOTO and Nobumori KINOSHITA, We have performed the electric conductivity measurements in the spin-density-wave (SDW) phase of (TMTSF)2ClO4 to clarify the dynamics of SDW. The temperature dependence of threshold electric field ET associated with the depinning of SDW was investigated with changing the SDW transition temperature TSDW by the control of anion ordering. The steep temperature dependence was observed for the highest TSDW (6 K) and was explained with the weak pinning by the impurity. The temperature dependence of ET becomes moderate with decreasing TSDW. For TSDW = 4 K, it is understood with the strong pinning. The crossover of pinning mechanism from the weak pinning to the strong one was discussed with taking account of the effective impurity concentration due to the disordered array of anion orientation., Physical Society of Japan
J. Phys. Soc. Jpn., Jan. 2000, [Reviewed]

〔Major achievements〕Non-linear conductance in SDW phase of (TMTSF)2ClO4
A. Hoshikawa; K. Nomura; S. Takasaki; J. Yamada; S. Nakatsuji; H. Anzai; M. Tokumoto; N. Kinoshita, We investigated the conductivity in the spin-density-wave phase of(TMTSF)(2)ClO4,. The non-linear conductivity was observed with the threshold electric field Er: The excess conductivity associated with the sliding of the SDW decreases rapidly below 0.3T(SDW) In low temperatures, the conductivity shows a great increase in high electric fields. The conductivity in high electric fields is independent of temperature. The mechanism of this conductivity is discussed in terms of the discommensuration structure., ELSEVIER SCIENCE SA
Synth. Met., Jun. 1999, [Reviewed]

〔Major achievements〕Sliding of the spin-density wave in (TMTSF)2ClO4
A. Hoshikawa; K. Nomura; T. Sambongi; S. Takasaki; J. Yamada; S. Nakatsuji; H. Anzai; M. Tokumoto and N. Kinoshita, We have performed conductivity measurements in the spin-density-wave (SDW) phase of(TMTSF)(2)ClO4 to investigate the sliding mechanism of SDW. From the temperature dependence of threshold electric field ET for a depinning of SDW, we found a change of pinning mechanism from the weak-pinning to the strong-pinning with decreasing the quenching rate of sample. At the low temperature, we also observed a significant increase of conductivity at much higher electric field. The behavior of I-V curves is independent of temperature and approximately described by Zener-like formula. This phenomenon suggests a new type of transport of SDW., ELSEVIER SCIENCE SA LAUSANNE
Synth. Met., Feb. 1997, [Reviewed]

中性子回折実験：中性子回折実験のすすめ　　　　　　　　　　　　　　　
星川晃範
ぶんせき, Nov. 2021

J-PARCにおける粉末中性子回折装置　　　　　　　　　　　　　　　
石垣 徹、米村 雅雄、星川 晃範、鳥居 周輝、神山 崇
波紋, Feb. 2015, [Reviewed]

〔Major achievements〕iMATERIAにおける自動試料交換搬送機構の開発　　　　　　　　　　　　　　　
星川 晃範、石垣 徹、米村 雅雄
波紋, Aug. 2013, [Reviewed]

J-PARCの物質・生命科学実験施設　　　　　　　　　　　　　　　
池田 一貴・奥 隆之・鈴木 淳市・武田 全康・星川 晃範・三宅 康博
工業材料, Aug. 2012

25pPSB-43 Disordor and physical properties in FeSr_2YCu_2O_<б+δ>, magnetic superconductor
Mochiku T.; Hata Y.; Hoshikawa A.; Iwase K.; Sulistyanintyas Dyah; Oguro H.; Ishigaki T.; Igawa N.; Tsuchiya Y.; Iwai H.; Yasuoka H.; Hirata K.
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2011

茨城県材料構造解析装置の現状について　　　　　　　　　　　　　　　
石垣 徹,星川 晃範,米村 雅雄,岩瀬 謙二,ディア スリスニ ンティアス,小黒 英俊,大石 亮子,森嶋 隆裕,森 一広,鬼柳 亮嗣, 茂筑 高士,神山 崇
波紋, Jan. 2010, [Reviewed]

24aYE-6 Phase transition of water ice under low temperature and low temperature
Fukazawa Hiroshi; Yamauchi Hiroki; Igawa Naoki; Utsumi Wataru; Hoshikawa Akinori
Meeting abstracts of the Physical Society of Japan, 29 Feb. 2008

粉末回折装置の概要と構造科学・材料開発に与えるインパクト　　　　　　　　　　　　　　　
石垣 徹; 星川晃範; 米村雅雄; 神山 崇; 鳥居周輝; 森嶋隆裕; 大石亮子
日本結晶学会誌, Feb. 2008, [Reviewed]

〔Major achievements〕Observation of Hydrogen in Methane Hydrate by Neutron Powder Diffraction　　　　　　　　　　　　　　　
Akinori Hoshikawa
J. Cryst. Soc. Jpn, Aug. 2007, [Reviewed], [Invited]

19aPS-70 Magnetism and Structure of Impurity-Doped Rutile
Mochiku T.; Hirata K.; Yamaki K.; Shimizu N.; Hoshikawa A.; Fujii H.; Yamada K.; Itoh S.; Kakeya I.; Kadowaki K.
Meeting Abstracts of the Physical Society of Japan, 2007

中性子回折によるメタンハイドレートの精密構造解析
井川直樹; 星川晃範; 石井慶信
日本中性子科学会誌「波紋」, Apr. 2006, [Reviewed]

Crystal structures and photocatalytic properties of protonated layered perovskite compounds
Nishimoto Shunsuke; Matsuda Motohide; Harjo Stefanus; Hoshikawa Akinori; Kamiyama Takashi; Ishigaki Toru; Miyake Michihiro
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2006

Structure and physical properties of impurity-doped TiO2
Mochiku Takashi; Fujii Hiroki; Ohnuma Masato; Yamada Katsura; Itoh Shinji; Kadowaki Kazuo; Hirata Kazuto; Yamaki Kazuhiro; Shimizu Natsumi; Hoshikawa Akinori; Wuernisha Tuerxun; Shikanai Fumihito; Mori Kazuhiro; Ishigaki Toru; Kamiyama Takashi
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2006

25aYK-11 Structure analysis of methane hydrates by neutron powder diffraction
Hoshikawa Akinori; Igawa Naoki; Yamauchi Hiroki; Ishii Yoshinobu
Meeting abstracts of the Physical Society of Japan, 04 Mar. 2005

Crystal structure and oxide ion conduction property of lanthanum gallate perovskite compounds
Kajitani Masahiro; Matsuda Motohide; Hoshikawa Akinori; Stefanus Harjo; Kamiyama Takashi; Ishigaki Toru; Izumi Fujio; Miyake Michihiro
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2005

Structural Analyses of Protonated Layered Perovskites, HLnTiO4 ( Ln = La, Nd and Y ), by Neutron Diffraction
NISHIMOTO Shunsuke; MATSUDA Motohide; HARJO Stefanus; HOSHIKAWA Akinori; KAMIYAMA Takashi; ISHIGAKI Toru; MIYAKE Michihiro
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2005

Synthesis and Structure of New Layered Perovskite Compounds, H_xNa_1-xLaTiO₄yH₂O
NISHIMOTO Shunsuke; MATSUDA Motohide; HARJO Stefanus; HOSHIKAWA Akinori; KAMIYAMA Takashi; ISHIGAKI Toru; MIYAKE Michihiro
Preprints of Annual Meeting of The Ceramic Society of Japan
Preprints of Fall Meeting of The Ceramic Society of Japan, 2005

〔Major achievements〕Maximum entropy method analysis of neutron powder diffraction patterns of methane deuterohydrates　　　　　　　　　　　　　　　
Akinori Hoshikawa; Naoki Igawa; Hiroki Yamauchi; Yoshinobu Ishii
Proceedings of the Fifth International Conference on Gas Hydrates, Jan. 2005

〔Major achievements〕二次元キラルフェリ磁性体の磁気構造
星川晃範
日本中性子科学会誌「波紋」, Oct. 2004, [Reviewed]

Neutron Diffraction during Thermal-Martensitic Transformation of Biocompatible Ti-Nb-Sn Alloy
HARJO Stefanus
材料とプロセス : 日本鉄鋼協会講演論文集 = Current advances in materials and processes : report of the ISIJ meeting, 01 Mar. 2004

30pXC-9 Correlation of the superconductivity with the super lattice structure in MgB_2 type superconductor CaAlSi
Sagayama H; Wakabayashi Y; Sawa H; Hoshikawa A; Harjo S.; Kamiyama T; Toki M; Uosato K; Ghosh A. K.; Tokunaga M; Tamegai T
Meeting Abstracts of the Physical Society of Japan, 2004

Quantum Beam Applied Analysis　　　　　　　　　　　　　　　
Ibaraki University

2017 - Present, The Japanese Society of Snow and Ice

2016 - Present, The Japan Institute of Energy

The Crystallographic Society of Japan

The Japanese Society for Neutron Science