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池内 和彦*; 脇本 秀一; 藤田 全基*; 福田 竜生; 梶本 亮一; 新井 正敏*
Physical Review B, 105(1), p.014508_1 - 014508_7, 2022/01
被引用回数:2 パーセンタイル:32.25(Materials Science, Multidisciplinary)Spin excitations of layered copper oxide show various characteristic features, depending on the carrier concentration. In this paper, we conducted inelastic neutron-scattering measurements on LaSrCuO (LSCO) with = 0, 0.075, 0.18, and 0.30 and LaSrNiO (LSNO) with 1/3 to clarify the origin of the intensity enhancement in the excitation spectrum of LSCO at the energy () of 16-19 meV [Phys. Rev. B , 224404 (2015), , 094416 (2016)]. We confirmed the presence of a peak structure in the dependence of the local spin susceptibility of superconducting (SC) LSCO with a peak energy of 16-19 meV where the spin excitations intersect optical phonon branches. A comparable peak structure is not observed in the insulating LaCuO, LSNO, and heavily overdoped LSCO with = 0.30. A dome-shaped dependence of the integrated intensity around the peak energies is revealed for the SC phase by summarizing the present and previously reported results. Furthermore, our phonon calculation on LCO shows the existence of two optical branches at 19 meV that could stabilize stripe alignment of carriers due to out-of-plane vibrations of Cu or O of the CuO planes. These results indicate the interplay among spin, charge, and lattice dynamics and suggest that the intensity enhancement is associated with their composite excitations.
佐藤 研太朗*; 池内 和彦*; 梶本 亮一; 脇本 秀一; 新井 正敏*; 藤田 全基*
Journal of the Physical Society of Japan, 89(11), p.114703_1 - 114703_7, 2020/11
被引用回数:6 パーセンタイル:49.7(Physics, Multidisciplinary)To elucidate the spin dynamics of LaSrCuO, which couples with the charge degree of freedom, the spin excitations spanning the characteristic energy ( 35-40 meV) are investigated for underdoped = 0.10 and optimally doped (OP) = 0.16 through inelastic neutron scattering measurements. Analysis based on a two-component picture of high-quality data clarified the possible coexistence of upright standing incommensurate (IC) excitations with gapless commensurate (C) excitations in the energy-momentum space. The IC component weakens the intensity toward with increasing energy transfer (), whereas the C component strengthens at high- regions. The analysis results imply that the superposition of two components with a particular intensity balance forms an hourglass-shaped excitation in appearance. Furthermore, the temperature dependence of the intensity of each component exhibits different behaviors; the IC component disappears near the pseudo-gap temperature () upon warming, whereas the C component is robust against temperature. These results suggest the itinerant electron spin nature and the localized magnetism of the parent LaCuO in IC and C excitations, respectively, similar to the spin excitations in the OP YBaCuO and HgBaCuO with higher superconducting-transition temperatures.
熊崎 由衣; 南山 泰之*; 池内 有為*; 上島 邦彦*; 岡山 将也*; 山田 一作*
第17回情報プロフェッショナルシンポジウム(INFOPRO 2020)予稿集, p.59 - 64, 2020/06
研究データの流通・利用の促進にあたっては、データに明確な利用条件が付与されることが重要である。研究データ利活用協議会・研究データライセンス小委員会では、研究データの利用条件を分かりやすく表示、または確認することを目的として「研究データの公開・利用条件指定ガイドライン」を策定し公開した。ここでは策定の背景や検討内容、ガイドラインの概要について紹介する。
山浦 淳一*; 平賀 晴弘*; 飯村 壮史*; 村場 善行*; Bang, J.*; 池内 和彦*; 中村 充孝; 稲村 泰弘; 本田 孝志*; 平石 雅俊*; et al.
Physical Review B, 99(22), p.220505_1 - 220505_6, 2019/06
被引用回数:3 パーセンタイル:16.02(Materials Science, Multidisciplinary)鉄系超伝導体LaFeAsODの非弾性中性子散乱実験により、超伝導転移温度26K以下において、5-15meVのエネルギー領域に新しい励起が生じることを見出した。なお、この励起は母物質であるLaFeAsOFでは現れない。14.5meVと11.1meVに現れる強い励起は水素の量子ラットリングまたはバンド運動に起因し、格子間サイトが2個以上のポテンシャル極小点を有する場合にのみ出現するものと結論付けた。
池内 和彦*; 中島 健次; 河村 聖子; 梶本 亮一; 脇本 秀一; 鈴木 謙介*; 藤田 全基*
AIP Advances (Internet), 8(10), p.101318_1 - 101318_5, 2018/10
被引用回数:0 パーセンタイル:0(Nanoscience & Nanotechnology)中性子散乱実験により、Al不純物を導入した実効ホール濃度0.25の銅酸化物超伝導体、LaSrCuAlOの巨大単結晶について、磁気励起を測定した。
池内 和彦*; 菊地 龍弥*; 中島 健次; 梶本 亮一; 脇本 秀一; 藤田 全基*
Physica B; Condensed Matter, 536, p.717 - 719, 2018/05
被引用回数:2 パーセンタイル:10.21(Physics, Condensed Matter)銅酸化物高温超伝導体の過剰ドープ領域における低エネルギーの磁気励起の構造の詳細を調べるために、我々は、LaSrCuOの中性子非弾性散乱実験を行った。過去に報告されたように、非整合な磁気相関に対応した = (0.5 , 0.5)/(0.5, 0.5 )を中心とした磁気励起を明瞭に観測した。それに加えて、を中心とした円環状の励起も観測された。円環の半径(=0.109)は、磁気相関の非整合性(=0.118)より小さい。このことは、円環状の磁気励起は非整合な磁気相関とはその原因を異にしていることを示唆している。LaSrCuOの磁気励起はこのように2種類の励起を持つことが示唆される。
池内 和彦*; 菊地 龍弥*; 中島 健次; 梶本 亮一; 脇本 秀一; 藤田 全基*
Journal of Physics; Conference Series, 969(1), p.012024_1 - 012024_5, 2018/04
被引用回数:1 パーセンタイル:52.54(Physics, Applied)Inelastic neutron scattering experiments were performed to investigate the effect of Fe substitution on the magnetic excitation spectra in a heavily hole-doped cuprate system LaSrCuFeO. Well-defined low-energy magnetic excitations, associated with a static magnetic order, were observed at the incommensurate (IC) positions. The incommensurability of 0.144 (r.l.u) was larger than that of 0.125 (r.l.u) in LSCO with = 0.25, suggesting an increase of incommensurability by Fe substitution. In addition to the obvious effect on IC excitations, we show the emergence of ring-shaped magnetic excitations by Fe-substitution. These results are incompatible with a simple pinning scenario of the stripe order, which is characterized by local spin correlations. The metallic aspect of the low-energy part of the magnetic excitation, which underlies high-temperature superconductivity in over-doped cuprate systems, would be enhanced/induced by Fe substitution.
脇本 秀一; 池内 和彦*; 新井 正敏; 藤田 全基*; 梶本 亮一; 川村 奨*; 松浦 直人*; 中島 健次; 山田 和芳*
JPS Conference Proceedings (Internet), 8, p.034013_1 - 034013_6, 2015/09
Previous neutron results of LaSrCuO (LSCO) by TOF measurements revealed that magnetic dynamical structure factor has a maximum at 18 meV. To clarify the origin of the maximum, we carried out 4 dimensional mapping of dynamical structure factor to see details of both magnons and phonons. We found that = 0 shows ordinary spin waves while = 0.08 shows a maximum at 18 meV where -independent phonon branch crosses. This imply that in superconducting compositions phonon may also indirectly related to the superconductivity.
斎藤 公明; 谷畑 勇夫*; 藤原 守; 齊藤 敬*; 下浦 享*; 大塚 孝治*; 恩田 裕一*; 星 正治*; 池内 嘉宏*; 高橋 史明; et al.
Journal of Environmental Radioactivity, 139, p.308 - 319, 2015/01
被引用回数:225 パーセンタイル:98.79(Environmental Sciences)The soil deposition density maps of -ray emitting radioactive nuclides from the Fukushima Daiichi Nuclear Power Plant (NPP) accident were constructed on the basis of the results from large-scale soil sampling. The 10,915 soil samples were collected at 2,168 locations. -rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that as of June 14, 2011 by taking into account the intrinsic decay constant of each nuclide. Finally the maps were created for Cs, Cs, I, Te and Ag. The radioactivity ratio of Cs to Cs was almost constant as 0.91 irrelevant to the soil sampling location. Effective doses for 50 years after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from other radioactive nuclides.
矢野 公彦; 北垣 徹; 池内 宏知; 涌井 遼平; 樋口 英俊; 鍛治 直也; 小泉 健治; 鷲谷 忠博
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.1554 - 1559, 2013/09
For the decommissioning of Fukushima Daiichi Nuclear Power Station (1F), defueling work for the fuel debris in the reactor core of Unit 1-3 is planned to be started within 10 years. Preferential items in the characterization of the fuel debris were identified for the defueling work at 1F, in which the procedure and handling tools were assumed from information of 1F and experience of Three Mile Island Unit 2 (TMI-2) accident. The candidates of defueling tools for 1F were selected from TMI-2 defueling tools. It was found out that they were categorized as 6 groups by their working principles. Important properties on the fuel debris for the defueling were picked up from considering influence of objective materials on their performance. The selected properties are shape, size, density, thermal conductivity, heat capacity, melting point, hardness, elastic modulus, and fracture toughness. In these properties, mechanical properties, i.e. hardness, elastic modulus, fracture toughness were identified as preferential items, because there are few data on that of fuel debris in the past severe accident studies.
飯村 壮史*; 松石 聡*; 宮川 仁*; 谷口 尚*; 鈴木 雄大*; 臼井 秀知*; 黒木 和彦*; 梶本 亮一; 中村 充孝; 稲村 泰弘; et al.
Physical Review B, 88(6), p.060501_1 - 060501_5, 2013/08
被引用回数:26 パーセンタイル:71.18(Materials Science, Multidisciplinary)We investigate the doping dependence of the magnetic excitations in two-superconducting-dome-system LaFeAsOD. Using inelastic neutron scattering, spin fluctuations at different wavenumbers were observed under both superconducting domes around and 0.4, but vanished at corresponding to the valley. Theoretical calculations indicate that the characteristic doping dependence of spin fluctuations is rationally explained as a consequence of the switching of the two intra-orbital nestings within Fe-3 and 3 by electron doping. The present results imply that the multi-orbital nature plays an important role in the doping and/or material dependence of the of the iron pnictide superconductors.
脇本 秀一; 石井 賢司; 木村 宏之*; 池内 和彦*; 吉田 雅洋*; 足立 匡*; Casa, D.*; 藤田 全基*; 福永 靖*; Gog, T.*; et al.
Physical Review B, 87(10), p.104511_1 - 104511_7, 2013/03
被引用回数:10 パーセンタイル:43.28(Materials Science, Multidisciplinary)We have performed resonant inelastic X-ray scattering (RIXS) near the Cu- edge on various cuprate superconductors, covering underdoped to heavily overdoped regimes and focusing on charge excitations inside the charge-transfer gap. RIXS measurements with = 9.003 keV on metallic LaSrCuO and BiPbSrCuO exhibit a dispersive intraband excitation below 4 eV, similar to that observed in the electron-doped NdCeCuO. This is the first observation of a dispersive intraband excitation in a hole-doped system, evidencing that both electron- and hole-doped systems have a similar dynamical charge correlation function.
池内 宏知; 佐野 雄一; 柴田 淳広; 小泉 務; 鷲谷 忠博
Journal of Nuclear Science and Technology, 50(2), p.169 - 180, 2013/02
被引用回数:7 パーセンタイル:49.06(Nuclear Science & Technology)高速炉燃料再処理において高重金属濃度の溶解液を得るため、燃料の短尺せん断片を用いた効率的な溶解プロセスを確立した。照射済MOX燃料の溶解速度に対するPu富化度,重金属濃度、及びせん断長さによる影響を調査した。その結果、照射済燃料の溶解速度はPu富化度の上昇とともに指数関数的に減少するが、未照射燃料と比べて100から1000倍程度増加することがわかった。浸透理論による速度論的解析の結果、重金属濃度の増加により固液比が減少し、燃料への硝酸の浸透性が低下することで溶解速度が低下することが示唆された。せん断長さの短尺化(長さ10mm)により、燃料の比表面積が増加することで硝酸の浸透性が改善され、高重金属濃度の条件においても従来再処理における濃度条件と同程度に溶解速度が維持されることがわかった。
石井 賢司; 筒井 健二; 池内 和彦*; Jarrige, I.; 水木 純一郎; 平賀 晴弘*; 山田 和芳*; 遠山 貴己*; 前川 禎通; 遠藤 康夫*; et al.
Physical Review B, 85(10), p.104509_1 - 104509_5, 2012/03
被引用回数:3 パーセンタイル:14.86(Materials Science, Multidisciplinary)We perform a resonant inelastic X-ray scattering (RIXS) study of Ni-substituted LaCuO and Cu-substituted LaNiO.Resonantly enhanced charge-transfer excitations are successfully observed by tuning the incident photon energy to the -edge of the substituted element. These excitations display a very weak momentum dependence, evidencing their local character. We find a shift in the energy of the onset edge of these features compared with the non-substituted compounds LaCuO and LaNiO. This shift is quantitatively reproduced by exact diagonalization calculations of the RIXS spectra. RIXS is shown to be a powerful tool to probe the electronic states of substituted elements and to understand their interaction with surrounding atoms.
池内 宏知; 柴田 淳広; 佐野 雄一; 小泉 務
Procedia Chemistry, 7, p.77 - 83, 2012/00
被引用回数:19 パーセンタイル:97.48(Chemistry, Analytical)照射済燃料の溶解速度及び不溶解残渣の発生量に与えるPu富化度の影響を調査した。Pu富化度30%未満、平均燃焼度40.1-63.7GWD/tの照射済燃料の溶解速度を、表面積理論に基づく速度論的解析に基づき評価した。その結果、照射済燃料の溶解速度は、未照射の場合と同様、Pu富化度とともに指数関数的に減少したが、照射により最大1000倍程度増加することが示唆された。不溶解残渣の発生量はPu富化度ともに増加し、これは照射段階におけるFP生成の促進に起因する可能性が高い。重金属初期質量の約1.3%が不溶解残渣として残った。
池内 宏知; 桂井 清道*; 佐野 雄一; 鷲谷 忠博
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Japan Atomic Energy Agency (JAEA) has been developing an efficient dissolution technology for irradiated MOX fuel in the framework of Fast Reactor Cycle Technology Development (FaCT) Project. In the fuel dissolution process for advanced aqueous reprocessing system named NEXT (New Extraction System for TRU Recovery), highly concentrated dissolution is required to adapt to the crystallization process. Optimum dissolution condition including short stroke shearing or pulverization of the irradiated fuel has been discussed, being based on the calculation results of continuous dissolver simulation code which reflects the results of dissolution tests using irradiated MOX fuel. We have been also developing rotary drum type continuous dissolver to adapt to the dissolution process for high heavy metal (U and Pu) concentration. This paper describes the summary and evaluation of R&D results on highly effective dissolution technology in the framework of FaCT Phase-I from 2006 to 2010.
石井 賢司; 池内 和彦*; Jarrige, I.; 水木 純一郎; 平賀 晴弘*; 山田 和芳*; 筒井 健二; 遠山 貴己*; 前川 禎通*; 遠藤 康夫*; et al.
Physica C, 470(Suppl.1), p.S155 - S157, 2010/12
被引用回数:0 パーセンタイル:0(Physics, Applied)Substitution of a specific element for a component is often used to elucidate its role in the superconductors. For a complete understanding of the substitution effect not only on the superconductivity but also on the electronic states, element-selective experiments are required. In this respect, resonant inelastic X-ray scattering (RIXS) has proven to be a powerful experimental technique enabling element-selective diagnosis of charge excitations. By tuning the incident photon energy to a given absorption edge of the element, the excitations involving the element are resonantly enhanced. In addition, RIXS has the advantage that momentum dependence can be measured. Using RIXS, we have measured the electronic excitations at the substituting sites in LaCuNiO and LaNiCuO. Near the absorption edge of the substituting element, namely the Ni -edge for LaCuNiO and the Cu -edge for LaNiCuO, charge transfer excitations from the 2 level of neighboring oxygen to the upper Hubbard band of the substituted Ni/Cu are observed. Experimental spectra are qualitatively reproduced by a theoretical calculation based on a - model.
吉田 雅洋; 石井 賢司; 池内 和彦*; Jarrige, I.; 村上 洋一*; 水木 純一郎; 筒井 健二; 遠山 貴己*; 前川 禎通*; 工藤 一貴*; et al.
Physica C, 470(Suppl.1), p.S145 - S146, 2010/12
被引用回数:4 パーセンタイル:21.9(Physics, Applied)SrCaCuO (SCCO), which is composed of two-leg ladders and edge-sharing chains, is the first superconducting cuprate without CuO planes. By substituting Ca for Sr, holes are transferred from the chains to the ladders. It was recently shown that charge ordering (CO) along the leg direction in the ladder occurs at and the periodicity is five times the unit length along the c axis. In order to investigate the electronic excitations associated with the CO, we carried out resonant inelastic X-ray scattering (RIXS) experiments for SCCO (). Cu- RIXS can directly probe the momentum-dependent electronic excitations related to the Cu site, which are resonantly enhanced by tuning the incident photon energy to the Cu -edge. We measured the q dependence of the intraband excitations, which is associated with the dynamics of doped holes in the Zhang-Rice singlet band. The intensity is enhanced at the momentum corresponding to the periodicity of the CO in , while the temperature dependence of the enhancement is different for and . We discuss the relationship between our experimental results and the occurrence of the CO.
Ellis, D. S.*; Kim, J.*; Hill, J. P.*; 脇本 秀一; Birgeneau, R. J.*; Shvyd'ko, Y.*; Casa, D.*; Gog, T.*; 石井 賢司; 池内 和彦*; et al.
Physical Review B, 81(8), p.085124_1 - 085124_12, 2010/02
被引用回数:40 パーセンタイル:80.3(Materials Science, Multidisciplinary)We present a comprehensive study of the temperature and doping dependence of the 500 meV peak observed at in resonant inelastic X-ray scattering (RIXS) experiments on LaCuO. The intensity of this peak persists above the Nel temperature ( = 320 K), but decreases gradually with increasing temperature, reaching zero at around = 500 K. The peak energy decreases with temperature in close quantitative accord with the behavior of the two-magnon Raman peak in LaCuO and, with suitable rescaling, agrees with the Raman peak shifts in EuBaCuO and KNiF. The overall dispersion of this excitation in the Brillouin zone is found to be in agreement with theoretical calculations for a two-magnon excitation. Upon doping, the peak intensity decreases analogous to the Raman mode intensity and appears to track the doping dependence of the spin-correlation length. Taken together, these observations strongly suggest that the 500 meV mode is magnetic in character and is likely a two-magnon excitation.
脇本 秀一; 木村 宏之*; 石井 賢司; 池内 和彦; 足立 匡*; 藤田 全基*; 加倉井 和久; 小池 洋二*; 水木 純一郎; 野田 幸男*; et al.
Physical Review Letters, 102(15), p.157001_1 - 157001_4, 2009/04
被引用回数:25 パーセンタイル:74.92(Physics, Multidisciplinary)Charge excitations in stripe-ordered 214 compounds, LaSrNiO and 1/8-doped La(Ba, Sr)CuO are studied using resonant inelastic X-ray scattering in hard X-ray regime. We are observing eV excitations with the momentum transfer corresponding to the charge stripe spatial period both for the diagonal (nickelate) and parallel (cuprates) stripes. They are interpreted as collective stripe excitations or anomalous softening of the charge excitonic modes of the in-gap states.