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山内 宏樹; Sari, D. P.*; 安井 幸夫*; 坂倉 輝俊*; 木村 宏之*; 中尾 朗子*; 大原 高志; 本田 孝志*; 樹神 克明; 井川 直樹; et al.
Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02
-Mn-type family alloys Mn have three-dimensional antiferromagnetic (AFM) corner-shared triangular network. The antiferromagnet MnRhSi shows magnetic short-range order (SRO) over a wide temperature range of approximately 500 K above the Nel temperature = 190 K. MnCoSi has the smallest lattice parameter and the lowest in the family compounds. The quantum critical point (QCP) from AFM to the quantum paramagnetic state is expected near a cubic lattice parameter of 6.15 of MnCoSi is only 140 K, quantum critical behavior is observed in MnCoSi as the enhancement of the electronic specific heat coefficient . We study how the magnetic SRO appears in MnCoSi by using neutron scattering, SR, and physical property measurements. The experimental results show that the neutron scattering intensity of the magnetic SRO does not change much regardless of the suppressed magnetic moment in the long-range magnetic ordered state compared to those of MnRhSi. The initial asymmetry drop ratio of SR above becomes small, and the magnetic SRO temperature is suppressed to 240 K. The results suggest that the MnCoSi is close to the QCP in the Mn system.
宇野 功一郎*; 中尾 淳*; 奥村 雅彦; 山口 瑛子; 小暮 敏博*; 矢内 純太*
日本土壌肥料学雑誌, 94(5), p.376 - 384, 2023/10
土壌のセシウム(Cs)吸着能の定量指標としてRadiocesium interception potential (RIP)が広く用いられてきたが、このRIPが実環境でのCsの分配係数()と必ずしも相関しないことがわかってきた。この原因を明らかにするため、より実環境に則した溶液を用いた測定やRIPとの比較、鉱物の構造評価を行った。その結果、カリウムイオンやアンモニウムイオンなどの競合陽イオンの濃度が重要であることや、鉱物自体の構造変化が重要であることがわかった。
小澤 竜也*; 藤原 理賀; 内原 猛*; 満田 節生*; 矢野 真一郎*; 玉造 博夢; 宗像 孝司*; 中尾 朗子*
Scientific Reports (Internet), 13, p.13750_1 - 13750_8, 2023/08
被引用回数:0 パーセンタイル:0.00(Multidisciplinary Sciences)圧力は、電子状態と原子配列の両方に作用し、物性を劇的に変化させる可能性を持つ。リン化マンガンMnPでは、約8GPaの等方圧力下において、Mn化合物で初めて、超伝導状態が観測された。本研究では、一軸応力がMnPの磁性および結晶構造に及ぼす影響を調査した。磁化測定と中性子回折実験により、0.04GPaという極めて低い一軸応力で、不可逆的な磁化応答が観測され、同時に、MnP型構造に特有の擬回転対称性を満たす結晶ドメインが誘起されることがわかった。不可逆的な磁化応答は、誘起された新たなドメインの構造により説明できることが判明した。一軸応力によって誘起される結晶ドメインに関する研究は過去に例がなく、我々はこの新現象を「原子再構成(AR)」と名付けることとした。我々は、AR現象に対する理解の深化は、誘電性、弾性、電気伝導、磁性、超伝導を含む物質の異方性を制御する結晶ドメイン工学の創出につながると期待している。
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
Synchrotron X-ray diffraction study revealed that NdSn ( = Rh and Ir) undergo structural phase transitions characterized by the wave vector =(1/2,1/2,0). Neutron diffraction study revealed antiferromagnetic ordering below = 1.65 and 1.42 K for NdRhSn and NdIrSn, respectively, which is similar to that previously reported for NdCoSn. These compounds show a magnetic susceptibility saturation behavior below approximately 3 K. The results indicate emergence of anomalous electronic correlation in NdSn ( = Co, Rh, and Ir) above .
松村 武*; 塚越 舜*; 上田 祥央*; 比嘉 野乃花*; 中尾 朗子*; 金子 耕士; 垣花 将司*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Journal of the Physical Society of Japan, 91(7), p.073703_1 - 073703_5, 2022/07
被引用回数:8 パーセンタイル:74.88(Physics, Multidisciplinary)Successive magnetic phase transitions in EuIrGe, an intermetallic compound with a body centered tetragonal lattice belonging to a polar space group I4mm, has been investigated by neutron diffraction and resonant X-ray diffraction. It is shown that EuIrGe exhibits an incommensurate longitudinal sinusoidalorder with (0, 0, 0.792) and m c-axis in the high temperature phase, which changes to a cycloidal order with = (, 0, 0.8) ( 0.017) and m ac-plane in the intermediate phase. In the low temperature phase, the cycloidal plane rotates by 45 to have =(, 0.8) (0.012). It is also pointed out that the X-ray scattering amplitude from odd-parity magnetic quadrupole due to the polar environment interfere with that from normal even-parity magnetic dipole in the magnetic ordered phase.
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
被引用回数:2 パーセンタイル:12.81(Chemistry, Physical)Hexagonal ferrite Ba(FeSc)O 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(FeSc)O 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(FeSc)O 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 of the helix for each x crystal is calculated from the relationship, , where is the incommensurability. The turn angle 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 cannot take values between 0 < < 90 and 170 < < 180.
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
被引用回数:47 パーセンタイル:95.20(Physics, Multidisciplinary)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
被引用回数:0 パーセンタイル:0.00(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 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*; 廣井 善二*
Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05
被引用回数:23 パーセンタイル:80.28(Chemistry, Physical)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
粘土鉱物は身近な鉱物の一つであり、環境中の元素挙動に大きな影響を及ぼすにも関わらず、未解明な点が多い。粘土鉱物の重要な特性の一つに、同程度の大きさのイオンによる置換反応(同形置換)があり、粘土鉱物の強い吸着力の要因の一つと考えられているが、実際にどの程度影響を及ぼすか評価されたことはない。本発表では、系統的なモデル作成と第一原理計算を用いることで、同形置換が剥離強度に与える影響を数値的に評価した結果を報告する。
内海 重宣*; 田中 誠也*; 丸山 建一*; 天児 寧*; 鬼柳 亮嗣; 中尾 朗子*; 森山 健太郎*; 石川 喜久*; 他9名*
ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09
被引用回数:5 パーセンタイル:22.76(Chemistry, Multidisciplinary)六方晶フェライトBa(FeSc)Oの磁気構造を解明し、さらなる応用開発を進めるためには、大型の高品質な単結晶を育成することが重要な第一歩である。本研究では、NaO-FeOフラックスを使用した自発結晶化法によって、さまざまなSc濃度のBa(FeSc)O単結晶の育成に成功した。得られた結晶は、高品質の単相Ba(FeSc)OであることがX線回折と元素分析により確認され、 = 0.128結晶の77Kの磁化測定では、ヘリマグネティックな挙動を示すことがわかった。=0.128結晶の中性子回折測定の結果、211K以下で磁気衛星反射が確認され、Ba(FeSc)Oがヘリ磁性物質であることが確認された。
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
被引用回数:43 パーセンタイル:89.85(Materials Science, Multidisciplinary)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.
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
被引用回数:25 パーセンタイル:79.61(Materials Science, Multidisciplinary)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。
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
被引用回数:2 パーセンタイル:10.89(Materials Science, Multidisciplinary)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
被引用回数:1 パーセンタイル:10.62(Physics, Multidisciplinary)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.
飯田 一樹*; 永井 佑紀; 石田 茂之*; 石角 元志*; 村井 直樹; Christianson, A. D.*; 吉田 紘行*; 稲村 泰弘; 中村 博樹; 中尾 朗子*; et al.
Physical Review B, 100(1), p.014506_1 - 014506_8, 2019/07
被引用回数:37 パーセンタイル:84.59(Materials Science, Multidisciplinary)パルス中性子散乱実験による鉄系超伝導体EuRbFeAsのスピン揺らぎ、磁気構造の測定を行い、同物質における超伝導体対称性などの議論を行った。
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
被引用回数:2 パーセンタイル:9.93(Chemistry, Inorganic & Nuclear)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
被引用回数:69 パーセンタイル:95.01(Physics, Multidisciplinary)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
被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)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.