金子 耕士; 川崎 卓郎; 仲村 愛*; 宗像 孝司*; 中尾 朗子*; 花島 隆泰*; 鬼柳 亮嗣; 大原 高志; 辺土 正人*; 仲間 隆男*; et al.
Journal of the Physical Society of Japan, 90(6), p.064704_1 - 064704_6, 2021/06
Multiple transition phenomena in divalent Eu compound EuAl with the tetragonal structure were investigated via single crystal time-of-flight neutron Laue technique. At 30 K below a charge-density-wave (CDW) transition, superlattice peaks emerge near nuclear Bragg peaks described by an ordering vector = (0 0 ). In contrast, magnetic peaks appear at with = 0.09 below = 15.4 K, and moves to with = 0.19 below =12.2 K, whereas no distinct change in the magnetic Bragg peak was detected at and . The structural modification with is characterized by an absence of the superlattice peak in (0 0 ). Considering an absence of splitting in magnetic peaks along , the structural transition is mainly ascribed to a displacement of Al ions within the tetragonal -plane. Complex incommensurate magnetic transitions are in stark contrast to a simple collinear commensurate structure in isovalent EuGa. This could stem from incompatible electronic structures with the CDW transition between two compounds.
Kwon, H.*; Pietrasiak, E.*; 大原 高志; 中尾 朗子*; Chae, B.*; Hwang, C.-C.*; Jung, D.*; Hwang, I.-C.*; Ko, Y. H.*; Kim, K.*; et al.
Inorganic Chemistry, 60(9), p.6403 - 6409, 2021/05
The synthesis of sandwich-shaped multinuclear silver complexes with planar penta- and tetranuclear wheel-shaped silver units and a central anion is reported, along with complete spectroscopic and structural characterization. An NMR mechanistic study reveals that silver complexes were formed in the following order: 2Ag 3Ag 5Ag 4Ag. The central hydroxides in 4Ag and 5Ag exhibit exotic physical properties due to the confined environment inside the complex. The size of these silver wheels can be tuned by changing the central anion or extracting/adding one silver atom. This study provides the facile way to synthesize discrete wheel-shaped multinuclear silver complexes and provides valuable insights into the dynamics of the self-assembly process.
矢島 健*; 日沼 洋陽*; 堀 智*; 岩崎 類*; 菅野 了次*; 大原 高志; 中尾 朗子*; 宗像 孝司*; 広井 善二*
Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05
Herein, we studied the crystalline compound LiGePS with the largest Li-ion conductivity thus far via a novel route based on a combination of single-crystal neutron diffraction experiments at low temperature and first-principles calculations, and found that a correlated migration of the densely packed Li ions governs the overall Li-ion conduction. The correlated migration mechanism provides us with guidelines on how to design efficient superionic conductors for more efficient batteries.
山口 瑛子; 浅野 育美*; 北川 結理*; Meng, C.*; 中尾 淳*; 奥村 雅彦
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.127 - 130, 2020/10
飯田 一樹*; 吉田 紘行*; 中尾 朗子*; Jeschke, H. O.*; Iqbal, Y.*; 中島 健次; 河村 聖子; 宗像 孝司*; 稲村 泰弘; 村井 直樹; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
鉱物センテニアライトCaCu(OD)Cl 0.6DOの結晶構造と磁気構造をシンクロトロンX線回折と中性子回折測定に密度汎関数理論(DFT)と疑似フェルミオン汎関数繰り込み群(PFFRG)の計算を組み合わせることで調べた。CaCu(OD)Cl 0.6DOではCuイオンは反強磁性と幾何学的に完全なカゴメネットワークを形成する。CuとCaイオン間のサイト間無秩序は見つからなかった。CaCu(OD)Cl 0.6DOは=7.2K以下で磁気秩序を示し、負のベクトルスピンキラリティーを持つ=0の磁気構造が現れる。0.3Kでの秩序モーメントは0.58(2)Bに抑えられている。我々のDFT計算では、この系が量子臨界点の近くにあり、--カゴメ反強磁性体の優れた実現であることを示唆している。
Hirschberger, M.*; 中島 多朗*; Kriener, M.*; 車地 崇*; Spitz, L.*; Gao, S.*; 吉川 明子*; 山崎 裕一*; 佐賀山 基*; 中尾 裕則*; et al.
Physical Review B, 101(22), p.220401_1 - 220401_6, 2020/06
For the skyrmion-hosting intermetallic GdPdSi with centrosymmetric hexagonal lattice and triangular net of rare earth sites, we report a thorough investigation of the magnetic phase diagram. Our work reveals a magnetic phase with an isotropic value of the critical field for all orientations, where the magnetic ordering vector is depinned from its preferred directions in the basal plane. The bulk nature of the skyrmion lattice and of other magnetic phases was evidenced by specific-heat measurements. Resistivity anisotropy, likely originating from partial gapping of the density of states along in this Ruderman-Kittel-Kasuya-Yoshida magnet, is picked up via the planar Hall effect (PHE). The PHE confirms the single- nature of the magnetic order when the field is in the hexagonal plane, and allows one to detect the preferred directions of . Several scenarios for the depinned phase are discussed on the basis of the data.
阿部 伸行*; 塩澤 俊介*; 松浦 慧介*; 佐賀山 基*; 中尾 朗子*; 大原 高志; 徳永 祐介*; 有馬 孝尚*
Physical Review B, 101(18), p.180407_1 - 180407_5, 2020/05
The correlation between magnetism and electric polarization in a chiral insulating magnet BaFeOCl has been investigated. The temperature dependence of magnetic susceptibility shows an anomaly at 564 K, suggesting the onset of antiferromagnetic order of Fe moments. Electric polarization appears in a magnetic field below TN due to the spin-direction-dependent metal-ligand hybridization. The direction of the electric polarization can be controlled in three-dimensional space by changing the direction of an external magnetic field. This compound also shows an antiferromagnetic-to-weak-ferromagnetic transition accompanied by a structural phase transition at 140 K.
中里 晟也*; 岩佐 和晃*; 橋本 大輔*; 塩澤 真未*; 桑原 慶太郎*; 中尾 裕則*; 佐賀山 基*; 石角 元志*; 大原 高志; 中尾 朗子*; et al.
JPS Conference Proceedings (Internet), 30, p.011128_1 - 011128_6, 2020/03
Successive phase transitions of IrSn (: La and Ce) were studied using neutron and X-ray diffraction techniques. A semimetal CeIrSn undergoes three phase transitions: an antiferromagnetic ordering characterized by a propagation vector = (1/2, 1/2, 2/5) below 0.6 K, a structural transformation with = (1/4, 1/4, 1/4) at 2.0 K, and another structural transformation with = (1/2, 1/2, 0) above room temperature. LaIrSn was confirmed to be a superconductor below 2.5 K under the = (1/2, 1/2, 0) structure that also appears above room temperature.
池田 修悟*; 金子 耕士; 田中 佑季*; 川崎 卓郎; 花島 隆泰*; 宗像 孝司*; 中尾 朗子*; 鬼柳 亮嗣; 大原 高志; 望月 健生*; et al.
Journal of the Physical Society of Japan, 89(1), p.014707_1 - 014707_7, 2020/01
Magnetism in EuNiIn has been studied by specific heat, magnetic susceptibility, magnetization, Eu Mssbauer spectroscopy, and neutron diffraction experiments. The specific heat shows two magnetic transitions at and at zero magnetic field. An antiferromagnetic ground state of EuNiIn has a uniaxial magnetic anisotropy along the b-axis, revealed by the magnetic susceptibility and the Mssbauer spectroscopy. Single crystal neutron diffraction experiments clarify that this antiferromagnetic structure in the ground state is characterized by the commensurate propagation vector = (1/2, 1/2, 1/2) which reveals no distinct anomaly at . The magnetization curve along the b-axis at 2 K shows four successive magnetic field-induced transitions up to 50 kOe and, reaches 7 /f.u. above 190 kOe, The magnetic phase diagram in EuNiIn has unique characteristics with five magnetic states in low magnetic field.
中根 僚宏*; 米山 翔太*; 兒玉 健*; 菊地 耕一*; 中尾 朗子*; 大原 高志; 東中 隆二*; 松田 達磨*; 青木 勇二*; 藤田 渉*
Dalton Transactions (Internet), 48(1), p.333 - 338, 2019/01
The two-dimensional quadratic lattice magnet, bis(glycolato)cobalt(II) ([Co(HOCHCO)]), showed anti-ferromagnetic ordering at 15.0 K and an abrupt increase in magnetisation at H = 22 600 Oe and 2 K, thereby acting as a metamagnet. Neutron diffraction studies suggested that the magnetic moment vectors of the Co(II) ions had an amplitude of 3.59 mB and were not aligned in a fully antiparallel fashion to those of their neighbours, which caused canting between the magnetic moment vectors in the sheet. The canting angle was determined to be 7.1deg. Canting induced net magnetisation in the sheet, but this magnetisation was cancelled between sheets. The magnetisations in the sheets were oriented parallel to the magnetic field at the critical magnetic field.
金子 耕士; Frontzek, M. D.*; 松田 雅昌*; 中尾 朗子*; 宗像 孝司*; 大原 高志; 垣花 将司*; 芳賀 芳範; 辺土 正人*; 仲間 隆男*; et al.
Journal of the Physical Society of Japan, 88, p.013702_1 - 013702_5, 2019/01
Magnetic transitions in chiral antiferromagnet EuPtSi were investigated by means of single crystal neutron diffraction. In the ground state, magnetic peaks emerge at positions represented by =. Upon heating, an additional magnetic peak splitting around 2.5 K was uncovered, indicating a presence of a first-order transition with =. An half-polarized neutron scattering for polarization parallel to Q reveled that polarization antiparallel to Q has stronger intensity in both magnetic phases. This feature clarifies single chiral character of helical structure with moments normal to the ordering vector in both ordered states. Under vertical magnetic field along [1,1,1] in the phase, magnetic peaks form hexagonal patterns in the equatorial scattering plane around nuclear. An ordering vector of the -phase has the similar size in the periodicity to , and could be a hallmark of a formation of skyrmion lattice in EuPtSi.
岩佐 和晃*; 伊賀 文俊*; 茂吉 武人*; 中尾 朗子*; 大原 高志
Journal of the Physical Society of Japan, 87(6), p.064705_1 - 064705_5, 2018/06
The magnetic-ordered state of a single-crystal sample of TbB has been studied with the high-precision neutron diffraction instrument SENJU installed at BL18 of the Materials and Life Science Facility in J-PARC. We observed new Bragg-reflection spots characterized by a propagation vector = (1/4, 1/4, 0) below the Nel temperature 20 K, in addition to the = (1/4, 1/4. 1/2) reported in the previous literatures. Because X-ray Thomson scattering measurements do not detect the superlattice reflections at 13 K, is a new magnetic-ordering propagation vector. The magnetic multi-q structure of TbB is similar to that of CeB, whereas the ratio of the amplitude to that of qM1 is smaller than in CeB. The combination of and is expected to assist the = (1/2, 0, 0) lattice modulation.
土屋 朋生*; 小林 亮太*; 窪田 崇秀*; 斉藤 耕太郎*; 小野 寛太*; 大原 高志; 中尾 朗子*; 高梨 弘毅*
Journal of Physics D; Applied Physics, 51(6), p.065001_1 - 065001_7, 2018/02
MnVAl Heusler alloy films were epitaxially grown on MgO(100) single-crystal substrates by ultra-high-vacuum magnetron sputtering. A2- and L21-type MnVAl order was controlled by the deposition temperature. A2-type MnVAl films showed no spontaneous magnetization, while L21-type MnVAl films showed ferrimagnetic behaviour with a maximum saturation magnetization of 220 emu/cm at room temperature (RT). An antiferromagnetic reflection was observed with neutron diffraction at RT for an A2-type MnVAl film deposited at 400C. A bilayer sample of the antiferromagnetic A2-type MnVAl and Fe showed an exchange bias of 120 Oe at 10 K.
社本 真一; 伊藤 孝; 大西 弘明; 山内 宏樹; 稲村 泰弘; 松浦 直人*; 赤津 光洋*; 樹神 克明; 中尾 朗子*; 茂吉 武人*; et al.
Physical Review B, 97(5), p.054429_1 - 054429_9, 2018/02
中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
五十嵐 正安*; 松本 朋浩*; 八木橋 不二夫*; 山下 浩*; 大原 高志; 花島 隆泰*; 中尾 朗子*; 茂吉 武人*; 佐藤 一彦*; 島田 茂*
Nature Communications (Internet), 8, p.140_1 - 140_8, 2017/07
Orthosilicic acid (Si(OH)) and its small condensation compounds are among the most important silicon compounds but have never been isolated, despite the long history of intense research due to their instability. These compounds would be highly useful building blocks for advanced materials if they become available at high purity. We developed a simple procedure to selectively synthesize orthosilicic acid, its dimer, cyclic trimer, and tetramer, as well as appropriate conditions to stabilize these species, in organic solvents. Isolation of orthosilicic acid, the dimer and the cyclic tetramer as hydrogen-bonded crystals with tetrabutylammonium halides and of the cyclic trimer as solvent-containing crystals was achieved. The solid-state structures of these compounds were unambiguously clarified by single crystal X-ray diffraction analysis and also by neutron diffraction study for orthosilicic acid. Based on these results, we also succeeded in developing a more practical synthetic procedure for high concentrations of stable orthosilicic acid stably in organic solvents via a simple hydrolysis of tetraalkoxysilanes.
川崎 卓郎; 金子 耕士; 仲村 愛*; 阿曽 尚文*; 辺土 正人*; 仲間 隆男*; 大原 高志; 鬼柳 亮嗣; 及川 健一; 田村 格良; et al.
Journal of the Physical Society of Japan, 85(11), p.114711_1 - 114711_5, 2016/11
The magnetic structure of the intermetallic compound EuGa was investigated using single-crystal neutron diffraction with TOF Laue technique on the new diffractometer SENJU at MLF of J-PARC. Despite of the high neutron absorption of Eu, a vast number of diffraction spots were observed without isotope enrichment. The magnetic reflections appeared at 2 below 16 K, indicating that the ordering vector is = (0, 0, 0). The continuous evolution of the magnetic reflection intensity below T follows a squared Brillouin function for = 7/2. By adopting a wavelength-dependent absorption collection, the magnetic structure of EuGa revealed that a nearly full magnetic moment of 6.4 B of Eu lies within the basal plane of the lattice.
堀口 直樹; 吉田 啓之; 中尾 泰大*; 金子 暁子*; 阿部 豊*
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11
The filtered venting system is used to realize the venting of the high pressure contaminated gas from the PCV to the outside of the nuclear power plant with suppressing the release of the radioactive materials. To operate the filtered venting system effectively, it is important to evaluate the decontamination performance of this system. The Venturi scrubber is the main component of the systems, and decontamination performance is affected by the hydrodynamic behavior in the Venturi scrubber. In this study, to develop the decontamination performance evaluation method of the filtered venting system, numerical simulation method to predict hydrodynamic behavior in the Venturi scrubber has been developed. In this paper, experimental observation under adiabatic (air-water) condition was conducted, and a numerical simulation code with one-dimensional two-fluid model was developed based on experimental results. In addition, numerical results were validated by comparing with experimental results. As the results, it was confirmed that it has the capability to evaluate the parameters with following accuracy, superficial gas velocity with +30%, the static pressure in throat part with 10%, superficial liquid velocity with 80%, droplet diameter with 30% and the droplet ratio with -50%.
増田 敏幸*; Arase, Junko*; 稲垣 佑亮*; 川幡 正俊*; 山口 健太郎*; 大原 高志; 中尾 朗子*; 門馬 洋行*; Kwon, E.*; 瀬高 渉*
Crystal Growth & Design, 16(8), p.4392 - 4401, 2016/08
Three-dimensional arrays of dipolar rotors were constructed as single crystals of molecular gyrotops, which are macrocage molecules with a bridged dipolar rotor. In this study, we synthesized novel molecular gyrotops with a five-membered heteroring, i.e., furan-diyl, thiophenediyl, and selenophene-diyl, and investigated the temperature-dependent orientation and rotation of the dipolar rotors inside the crystal.
大原 高志; 鬼柳 亮嗣; 及川 健一; 金子 耕士; 川崎 卓郎; 田村 格良; 中尾 朗子*; 花島 隆泰*; 宗像 孝司*; 茂吉 武人*; et al.
Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02
SENJU, a time-of-flight Laue-type single-crystal neutron diffractometer, was developed at the Materials and Life Science Experimental Facility (MLF) of the Japan Accelerator Research Complex (J-PARC). Molecular structure analysis of a sub-millimeter taurine crystal and magnetic structure analysis of a MnF crystal were performed to evaluate its performance.