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論文

新奇超伝導体UTe単結晶の純良化; $T_{rm c}$ 向上と多重超伝導相図

酒井宏典; 芳賀芳範

固体物理, 58(10), p.529 - 536, 2023/10

我々は過剰ウランを含む溶融塩フラックス法により、高品質UTe単結晶の育成に成功した。また、この純良結晶を用いて、磁気困難軸方向に25Tまでの磁場を印加し、超伝導相図を調べた。

論文

Site-specific relaxation of peptide bond planarity induced by electrically attracted proton/deuteron observed by neutron crystallography

千葉薫*; 松井拓郎*; 茶竹俊行*; 大原高志; 田中伊知朗*; 油谷克英*; 新村信雄*

Protein Science, 32(10), p.e4765_1 - e4765_13, 2023/10

https://doi.org/10.1002/pro.4765

被引用回数：0 パーセンタイル：0(Biochemistry & Molecular Biology)

In structural biology, peptide bonds, fundamental linkages between hundreds of amino acids, of which a protein molecule is composed, have been commonly treated as a plane structure just as Linus Pauling et al. proposed. In this paper, a site-specific peptide bond relaxation mechanism by deuterons whose localization has been suggested by neutron crystallography is proposed. A comprehensive study using X-ray and neutron diffraction and $^{15}$ N chemical shifts of individual amide nitrogen atoms within the same peptide bond strongly suggests the relaxation of the electronic resonance structure because of site-specific modulation by protons/deuterons localized on the electron orbital of the carbonyl oxygen.

論文

Development of an iron(II) complex exhibiting thermal- and photoinduced double proton-transfer-coupled spin transition in a short hydrogen bond

中西匠*; 堀優太*; 重田育照*; 佐藤寛泰*; 鬼柳亮嗣; 宗像孝司*; 大原高志; 岡澤厚*; 島田林太郎*; 坂本章*; et al.

Journal of the American Chemical Society, 145(35), p.19177 - 19181, 2023/08

https://doi.org/10.1021/jacs.3c06323

被引用回数：0 パーセンタイル：0(Chemistry, Multidisciplinary)

Multiple proton transfer (PT) controllable by external stimuli plays a crucial role in fundamental chemistry, biological activity, and material science. However, in crystalline systems, controlling multiple PT, which results in a distinct protonation state, remains challenging. In this study, we developed a novel tridentate ligand and iron(II) complex with a short hydrogen bond (HB) that exhibits a PT-coupled spin transition (PCST). Single-crystal X-ray and neutron diffraction measurements revealed that the positions of the two protons in the complex can be controlled by temperature and photoirradiation based on the thermal- and photoinduced PCST. The obtained results suggest that designing molecules that form short HBs is a promising approach for developing multiple PT systems in crystals.

論文

Magnetic ordering and structural phase transitions of Nd $_{3}$ $_{4}$ Sn $_{13}$ ( = Rh and Ir)

下田愛海*; 岩佐和晃*; 桑原慶太郎*; 佐賀山基*; 中尾裕則*; 石角元志*; 大原高志; 中尾朗子*; 星川晃範*; 石垣徹*

JPS Conference Proceedings (Internet), 38, p.011091_1 - 011091_6, 2023/05

https://doi.org/10.7566/JPSCP.38.011091

Synchrotron X-ray diffraction study revealed that Nd $_{3}$ $_{4}$ Sn $_{13}$ ( = Rh and Ir) undergo structural phase transitions characterized by the wave vector $_{rm L}$ =(1/2,1/2,0). Neutron diffraction study revealed antiferromagnetic ordering below $_{rm N}$ = 1.65 and 1.42 K for Nd $_{3}$ Rh $_{4}$ Sn $_{13}$ and Nd $_{3}$ Ir $_{4}$ Sn $_{13}$ , respectively, which is similar to that previously reported for Nd $_{3}$ Co $_{4}$ Sn $_{13}$ . These compounds show a magnetic susceptibility saturation behavior below approximately 3 K. The results indicate emergence of anomalous electronic correlation in Nd $_{3}$ $_{4}$ Sn $_{13}$ ( = Co, Rh, and Ir) above $_{rm N}$ .

論文

Observation of proton-transfer-coupled spin transition by single-crystal neutron-diffraction measurement

中西匠*; 堀優太*; 重田育照*; 佐藤寛泰*; Wu, S.-Q.*; 鬼柳亮嗣; 宗像孝司*; 大原高志; 佐藤治*

Physical Chemistry Chemical Physics, 25(17), p.12394 - 12400, 2023/05

https://doi.org/10.1039/D3CP00527E

被引用回数：1 パーセンタイル：56.86(Chemistry, Physical)

The application of single-crystal neutron diffraction (SCND) to observe proton-transfer phenomena in crystalline compounds exhibiting unusual protonation states or proton dynamics has garnered significant research interest in recent years. However, proton tautomerism, which results in different protonation states before and after proton transfer, has never been observed using the SCND technique. Thus, to observe the proton tautomerism phenomenon by SCND measurements, we developed an iron(II) complex that forms a large crystal and exhibits a proton-transfer-coupled spin transition (PCST). The presence of the two types of proton tautomers was determined by conventional analysis of the proton position by X-ray crystallography, infrared spectroscopy, and density functional theory calculations. Finally, our results confirmed that proton tautomerism was successfully observed for the first time using variable-temperature SCND measurements.

論文

Incommensurate helimagnetic structure of Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ determined by single-crystal neutron diffraction

田中誠也*; 鬼柳亮嗣; 石川喜久*; 天児寧*; 飯山拓*; 二村竜祐*; 丸山建一*; 内海重宣*

Physical Review Materials (Internet), 7(1), p.014403_1 - 014403_11, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014403

被引用回数：0 パーセンタイル：0(Materials Science, Multidisciplinary)

Sc-substituted hexagonal ferrite Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ has an incommensurate helimagnetic structure. However, the incommensurate helimagnetic structure has not been sufficiently determined, and the mechanism via which the helimagnetism develops has not been studied. Time-of-flight single-crystal neutron diffraction measurements were performed on single-crystal samples of Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ with Sc concentrations of x = 0, 0.128, 0.153, and 0.193. The magnetic structure analyses revealed that the helimagnetic structure of Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ is a cone type whose base is in the ab plane and height is in the c-axis direction. The magnetic moments of Fe2(4), Fe4(4 $f_{2}$ ), and Fe5(12) are aligned with distinct angles, leading to the helimagnetic structure of Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ , and can be explained by assuming that there is an antiferromagnetic superexchange interaction $J_{5}$ between Fe2(4) and Fe5(12) that is negligible in the x = 0 crystal. The shorter bond distance of Fe2-O1 in Sc-rich crystals revealed by the crystal structure analyses enhances the superexchange interaction $J_{5}$ . The relatively strong $J_{5}$ leads to competition among the three superexchange interactions, $J_{3}$ , $J_{4}$ , and $J_{5}$ , resulting in the development of the helimagnetic structure. These findings facilitate the understanding of the essentials of the basic magnetic material BaFe $_{12}$ O $_{19}$ .

論文

Single crystal growth of superconducting UTe by molten salt flux method

酒井宏典; Opletal, P.; 常盤欣文; 山本悦嗣; 徳永陽; 神戸振作; 芳賀芳範

Physical Review Materials (Internet), 6(7), p.073401_1 - 073401_10, 2022/07

https://doi.org/10.1103/PhysRevMaterials.6.073401

被引用回数：16 パーセンタイル：88.61(Materials Science, Multidisciplinary)

スピン三重項超伝導体UTeの新規合成ルートとして溶融塩フラックス法を適用した。合成条件を最適化した結果、今までで最高の超伝導転移温度 $T_{rm c}=2.1$ Kを記録した。これらの単結晶は、著しく大きな残留抵抗率比を示し、 $T_{rm c}$ 以下における残留比熱も小さくなった。これらはウラン空孔による結晶欠陥が減少したことを示しており、溶融塩フラックス中の余剰金属ウランが、還元雰囲気を作り、四価ウランが五価となるのを防ぎウラン空孔生成を抑制しているようだ。また、低融点フラックスがテルルの蒸発を防ぐ効果も期待できる。

論文

単結晶中性子回折法の開発と高精度な水素原子位置の決定に基づいた構造化学研究

大原高志

日本結晶学会誌, 64(2), p.132 - 139, 2022/05

https://doi.org/10.5940/jcrsj.64.132

中性子を用いる単結晶中性子回折法は原子核の位置を直接観察できることに加えて水素原子に対する感度が高いことから、結晶中の水素原子位置を高精度で確実に観察できる強力な手法となる。日本国内では1990年代末からJRR-3研究用原子炉を中心に単結晶中性子回折計の開発が進み、金属錯体など格子体積の比較的大きい分子性結晶における水素原子の観察が現実的になるとともに、より大強度の中性子源であるJ-PARCの建設が始まった。そのなかで筆者は単結晶中性子回折計の開発と並行して、単結晶中性子構造解析による分子性結晶中の水素原子の確実な観察を基にした研究を展開してきた。本稿では、これらの水素原子が鍵となる研究について概説する。

論文

Single-crystal structure analysis of non-deuterated triglycine sulfate by neutron diffraction at 20 and 298 K; A New disorder model for the 298 K structure

寺澤有果菜*; 大原高志; 佐藤宗太*; 吉田知史*; 朝日透*

Acta Crystallographica Section E; Crystallographic Communications (Internet), 78(3), p.306 - 312, 2022/03

https://doi.org/10.1107/S2056989022000858

Precise single-crystal structure analyses of the title compound, nondeuterated triglycine sulfate (HTGS) at 20 K and 298 K were undertaken using time-of-flight neutron diffraction data. At 20 K for the O-H...O hydrogen bond between the glycinium cation and the zwitterionic, unprotonated glycine molecule that is associated with the ferroelectric behaviour of HTGS. Two reasonable structures for the same three atoms were refined for the 298 K dataset. One is a single-minimum potential-energy model, having the H atom with a large ellipticity along the bond path between the O atoms. The other is a double-minimum potential-energy model having two H atom sites with occupancies of 0.876 and 0.124.

論文

Improvement of nano-polycrystalline diamond anvil cells with Zr-based bulk metallic glass cylinder for higher pressures; Application to Laue-TOF diffractometer

山下恵史朗*; 小松一生*; 大原高志; 宗像孝司*; 入舩徹男*; 新名亨*; 杉山和正*; 川又透*; 鍵裕之*

High Pressure Research, 42(1), p.121 - 135, 2022/03

https://doi.org/10.1080/08957959.2022.2045982

被引用回数：3 パーセンタイル：58.88(Physics, Multidisciplinary)

We improved diamond anvil cells with a tubular frame made of Zr-based bulk metallic glass and nano-polycrystalline diamond anvils for single-crystal neutron diffraction. The thicker tubular frame was confirmed through experimentation as stably generating 4.5 GPa. Its feasibility for neutron diffraction was assessed at the Laue-TOF diffractometer at the BL18 (SENJU) beamline in the MLF J-PARC using time-resolved two-dimensional detectors covering wide solid angles. In addition to ambient-pressure measurements of NH $_{4}$ Cl, diffraction patterns of a high-pressure phase of ice were also collected in-situ. The obtained intensities are of refinable quality sufficient for structure analysis.

論文

Magnetic phase diagram of helimagnetic Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ (0 x 0.2) hexagonal ferrite

丸山建一*; 田中誠也*; 鬼柳亮嗣; 中尾朗子*; 森山健太郎*; 石川喜久*; 天児寧*; 飯山拓*; 二村竜祐*; 内海重宣*; et al.

Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02

https://doi.org/10.1016/j.jallcom.2021.162125

被引用回数：2 パーセンタイル：16.86(Chemistry, Physical)

Hexagonal ferrite Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ is an important magnetic oxide material in both science and engineering because it exhibits helimagnetism around room temperature (300 K). In this study, the magnetic phase diagram of Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ consisting of ferri-, heli-, antiferro-, and paramagnetic phases has been completed through magnetization and neutron diffraction measurements. The magnetic phase transition temperature to paramagnetism decreases with the increase in x, and the temperature at which the magnetization reaches a maximum, which corresponds to the magnetic phase transition from heli- to ferrimagnetism, is determined for low x crystals. The temperatures at which helimagnetism appears are precisely determined by observing the magnetic satellite reflection peaks in neutron diffraction at various temperatures, which characterize helimagnetism. Based on these results, the magnetic phase diagram of the Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ system is constructed in the T-x plane. Helimagnetism appears at x 0.06, and magnetism with antiferromagnetic components appears as the extension phase of helimagnetism at x 0.19 through the coexistence region. The turn angle $phi_{0}$ of the helix for each x crystal is calculated from the relationship, $phi_{0} = 2pidelta$ , where is the incommensurability. The turn angle $phi_{0}$ decreases with the increase in temperature for the same x crystal, and increases with the increase in x at the same temperature. Furthermore, it is found that there are clear thresholds at which $phi_{0}$ cannot take values between 0 $^{circ}$ < $phi_{0}$ < 90 $^{circ}$ and 170 $^{circ}$ < $phi_{0}$ < 180 $^{circ}$ .

論文

Insights into proton dynamics in a photofunctional salt-cocrystal continuum; Single-crystal X-ray, neutron diffraction, and Hirshfeld atom refinement

矢野喜男*; 小野利和*; 大原高志; 久枝良雄*

Chemistry; A European Journal, 27(71), p.17802 - 17807, 2021/12

https://doi.org/10.1002/chem.202103044

被引用回数：4 パーセンタイル：30.82(Chemistry, Multidisciplinary)

X-ray diffraction, neutron diffraction, and Hirshfeld atom refinement (HAR) demonstrate that the slight difference of the N...H...O hydrogen bonds (HBs) in crystalline metastable acid-base complexes gives distinct photoluminescent properties. Our results contribute to understanding the complicated relationship between photofunction and proton dynamics in acid-base complexes, helping to create novel photofunctional materials.

論文

synchrotron radiation observation of deformation and annealing processes of aluminum single crystal

城鮎美*; 岡田達也*; 菖蒲敬久

Mechanical Engineering Journal (Internet), 8(6), p.21-00106_1 - 21-00106_8, 2021/12

https://doi.org/10.1299/mej.21-00106

本研究の目的は、SPring-8からの放射光X線を使用して、アルミニウム単結晶の変形および熱処理プロセス中のその場観察を実施することである。縦方向に平行な111配向を有するアルミニウム単結晶サンプルをブリッジマン法により成長させ、インライン引張装置を使用して、サンプルを室温で公称ひずみ0.08まで変形させた。その後、480 $^{circ}$ Cの熱処理を実施した。実験では二次元検出器を使用し、前述の過程中のサンプルから複数の回折線を検出した。その結果、初期段階から、X線が照射された領域は、サブグレイン微細構造に起因する小さな配向差を有する3つの領域で構成されていることを確認した。回折スポット強度の詳細な分析から、引張ひずみの増加に伴い、サブグレイン微細構造が転位微細構造に変化していることが分かった。そして変形後の熱処理中に、再結晶粒からの回折スポットは、480 $^{circ}$ Cに達した後180秒から出現し、変形マトリックスと再結晶粒からの回折スポットの共存は約22秒間しか持続しなかったことを確認した。この結果を詳細に分析すると、変形マトリックスと再結晶粒の間の境界の移動速度は、数マイクロメートル/秒のオーダーであると推定された。

論文

Programmable synthesis of silver wheels

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

https://doi.org/10.1021/acs.inorgchem.1c00106

被引用回数：0 パーセンタイル：0.01(Chemistry, Inorganic & Nuclear)

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 $^{rm H2O}$ 5Ag $^{rm OH}$ 4Ag $^{rm OH}$ . The central hydroxides in 4Ag $^{rm OH}$ and 5Ag $^{rm OH}$ 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.

論文

Correlated Li-ion migration in the superionic conductor Li $_{10}$ GeP $_{2}$ S $_{12}$

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*; 廣井善二*

Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05

https://doi.org/10.1039/D1TA00552A

被引用回数：19 パーセンタイル：80.41(Chemistry, Physical)

Herein, we studied the crystalline compound Li $_{10}$ GeP $_{2}$ S $_{12}$ 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.

論文

Magnetically induced electric polarization in Ba $_{3}$ Fe $_{2}$ O $_{5}$ Cl $_{2}$ with tunable direction in three dimensions

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

https://doi.org/10.1103/PhysRevB.101.180407

被引用回数：2 パーセンタイル：12.9(Materials Science, Multidisciplinary)

The correlation between magnetism and electric polarization in a chiral insulating magnet Ba $_{3}$ Fe $_{2}$ O $_{5}$ Cl $_{2}$ has been investigated. The temperature dependence of magnetic susceptibility shows an anomaly at 564 K, suggesting the onset of antiferromagnetic order of Fe $^{3+}$ 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.

論文

Successive phase transitions in $R_{3}$ Ir $_{4}$ Sn $_{13}$ (: La and Ce) investigated using neutron and X-ray diffraction

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

https://doi.org/10.7566/JPSCP.30.011128

Successive phase transitions of $R_{3}$ Ir $_{4}$ Sn $_{13}$ (: La and Ce) were studied using neutron and X-ray diffraction techniques. A semimetal Ce $_{3}$ Ir $_{4}$ Sn $_{13}$ undergoes three phase transitions: an antiferromagnetic ordering characterized by a propagation vector $q_{rm M}$ = (1/2, 1/2, 2/5) below 0.6 K, a structural transformation with $q_{rm S2}$ = (1/4, 1/4, 1/4) at 2.0 K, and another structural transformation with $q_{rm S1}$ = (1/2, 1/2, 0) above room temperature. La $_{3}$ Ir $_{4}$ Sn $_{13}$ was confirmed to be a superconductor below 2.5 K under the $q_{rm S1}$ = (1/2, 1/2, 0) structure that also appears above room temperature.

論文

Crystal structure and cation distribution of the X-type hexaferrite Sr $_{2}$ Co $_{2}$ Fe $_{28}$ O $_{46}$

駒淵舞*; 漆原大典*; 浅香透*; 福田功一郎*; 大原高志; 宗像孝司*; 石川喜久*

Journal of the Physical Society of Japan, 89(3), p.034601_1 - 034601_5, 2020/03

https://doi.org/10.7566/JPSJ.89.034601

被引用回数：2 パーセンタイル：22.16(Physics, Multidisciplinary)

The crystal structure of an X-type hexaferrite Sr $_{2}$ Co $_{2}$ Fe $_{28}$ O $_{46}$ was investigated by the X-ray and neutron diffraction methods for a single crystal. Sr $_{2}$ Co $_{2}$ Fe $_{28}$ O $_{46}$ has the crystal structure described as a space group () and its lattice constants are = 5.9165(2) ; and = 84.1395(33) ; at 843 K. Co ions are almost localized in the octahedral site () in the middle of S $^{*}$ S $^{*}$ blocks. In addition, the adjacent octahedral and tetrahedral sites to site contain the significant number of Co $^{2+}$ .

論文

Time-controlled synthesis of the 3D coordination polymer U(1,2,3-Hbtc) $_{2}$ followed by the formation of molecular poly-oxo cluster { $rm U$_{14}$$ } containing hemimellitate uranium(IV)

Dufaye, M.*; Martin, N. P.*; Duval, S.*; Volkringer, C.*; 池田篤史; Loiseau, T.*

RSC Advances (Internet), 9(40), p.22795 - 22804, 2019/07

AA2019-0270.pdf:1.14MB

https://doi.org/10.1039/C9RA03707A

被引用回数：13 パーセンタイル：50.23(Chemistry, Multidisciplinary)

4価ウラン(U(IV))のヘミメリット酸との配位化合物がアセトン+水溶媒中で2種類合成され、構造同定された。水分量を調整したアセトン溶媒中では、U(IV)の加水分解はゆっくりと起こり、その結果、{ $rm U$_{12}$$ }や{ $rm U$_{14}$$ }といった特異なポリオキソ-U(IV)クラスターが生成していることを確認した。

論文

Magnetic, thermal, and neutron diffraction studies of a coordination polymer; bis(glycolato)cobalt(II)

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

https://doi.org/10.1039/C8DT04358B

被引用回数：2 パーセンタイル：11.34(Chemistry, Inorganic & Nuclear)

The two-dimensional quadratic lattice magnet, bis(glycolato)cobalt(II) ([Co(HOCH $_{2}$ CO $_{2}$ ) $_{2}$ ]), 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.