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Microscopic dynamics of lithium diffusion in single crystal of the solid-state electrolyte La$$_{2/3-x}$$Li$$_{3x}$$TiO$$_{3}$$ (x = 0.13) studied by quasielastic neutron scattering

松浦 直人*; 藤原 靖幸*; 森分 博紀*; 尾原 幸治*; 川北 至信

Physical Review B, 104(9), p.094305_1 - 094305_7, 2021/09


Quasielastic neutron scattering (QENS) measurements combined with first principles based molecular dynamics calculations were conducted to study the dynamics of Li$$^{+}$$ ions in a solid-state electrolyte La$$_{2/3-x}$$Li$$_{3x}$$TiO$$_{3}$$ (LLTO) with $$x = 0.13$$. By using a large $$^{7}$$Li-enriched single crystal sample, a QENS signal was clearly observed along the three principal axes [110], [111], and [001] at a temperature ($$T$$) of 600 K. Wave vector dependence of the linewidth of the QENS signal along each direction was explained well using the Chudley-Elliot model for jumps between the A sites of the perovskite lattice through the bottleneck square, which was also supported by molecular dynamics calculations. The estimated self-diffusion coefficient of Li$$^{+}$$ ($$D_{rm Li}$$) in the ab plane was slightly larger than that along the c axis, suggesting quasi-isotropic diffusion, that is, the three-dimensional diffusion of Li$$^{+}$$ ions. The decrease in $$D_{rm Li}$$ with decreasing $$T$$ was reasonably explained by a thermal activation process with the activation energy determined from ionic-conductivity measurements. Furthermore, the estimated values of the self-diffusion coefficient are comparable to those in the sulfide-based Li$$^{+}$$ ion conductor, Li$$_{7}$$P$$_{3}$$S$$_{11}$$, with 10 times larger ionic conductivity, which clarifies how to understand the Li conduction mechanism in LLTO and Li$$_{7}$$P$$_{3}$$S$$_{11}$$ in a unified manner.


Spin glass behavior and magnetic boson peak in a structural glass of a magnetic ionic liquid

古府 麻衣子; 綿貫 竜太*; 榊原 俊郎*; 河村 聖子; 中島 健次; 松浦 直人*; 上木 岳士*; 阿久津 和宏*; 山室 修*

Scientific Reports (Internet), 11(1), p.12098_1 - 12098_8, 2021/06

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

Glassy magnetic behavior has been observed in a wide range of crystalline magnetic materials called spin glass. Here, we report spin glass behavior in a structural glass of a magnetic ionic liquid, C4mimFeCl$$_{4}$$. Magnetization measurements demonstrate that an antiferromagnetic ordering occurs at $$T_{rm N}$$ = 2.3 K in the crystalline state, while a spin glass transition occurs at $$T_{rm SG}$$ = 0.4 K in the structural glass state. In addition, localized magnetic excitations were found in the spin glass state by inelastic neutron scattering, in contrast to spin-wave excitations in the ordered phase of the crystalline sample. The localized excitation was scaled by the Bose population factor below $$T_{rm SG}$$ and gradually disappeared above $$T_{rm SG}$$. This feature is highly reminiscent of boson peaks commonly observed in structural glasses. We suggest the "magnetic" boson peak to be one of the inherent dynamics of a spin glass state.


Position dependency of the scattered intensity in the time-of-flight backscattering spectrometer DNA

松浦 直人*; 山田 武*; 富永 大輝*; 小林 誠*; 中川 洋; 川北 至信

JPS Conference Proceedings (Internet), 33, p.011068_1 - 011068_6, 2021/03



Position-encoded automatic cell elevator for BL02, J-PARC MLF

富永 大輝*; 小林 誠*; 山田 武*; 松浦 直人*; 川北 至信; 笠井 聡*

JPS Conference Proceedings (Internet), 33, p.011095_1 - 011095_5, 2021/03

トップローディング型冷凍機用の垂直移動型試料交換機が、J-PARC MLFのBL02に設置された中性子分光器の利用支援のために開発された。PEACEと名付けられたこの試料交換機は、中性子照射位置での試料位置の再現性を、PEEKと呼ぶ物質でできたガイドを利用して制御している。3つの試料位置でのバックグラウンド散乱のプロファイルの変化は$$pm$$1.6%以内であることが分かった。この結果は、垂直軸からの試料位置の偏差が$$pm$$0.3mmであることを考えると妥当である。


Magnetism induced by interlayer electrons in the quasi-two-dimensional electride Y$$_{2}$$C; Inelastic neutron scattering study

玉造 博夢; 村上 洋一*; 倉本 義夫*; 佐賀山 基*; 松浦 直人*; 川北 至信; 松石 聡*; 鷲尾 康仁*; 井下 猛*; 浜田 典昭*; et al.

Physical Review B, 102(22), p.224406_1 - 224406_5, 2020/12

 被引用回数:3 パーセンタイル:58.93(Materials Science, Multidisciplinary)

Magnetic excitations in layered electride Y$$_{2}$$C have been found by inelastic neutron scattering. We have observed weak but clear magnetic scattering around the wave number $$Q = 0$$, but no magnetic order down to the lowest temperature measured (7 K). The imaginary part of the dynamical susceptibility deduced is well described by the Lorentz function of energy $$E$$ for each momentum $$Q$$. The width $$mathit{Gamma}(Q)$$ of the Lorentzian is proportional to $$Q(Q^2+kappa^{2})$$ with $$kappa^{-1} sim 4{rm AA}$$ at $$T=7$$ K. We have also found that with increasing $$Q$$ the magnetic form factor decays faster than that of a $$4d$$ electron in a single Y atom, which indicates a more extended magnetic moment in Y$$_{2}$$C. These results provide experimental evidence that the itinerant magnetism in Y$$_{2}$$C originates from the anionic electrons that reside in the interlayers. The Curie-Weiss-like behavior of the magnetic susceptibility reported in Y$$_{2}$$C is ascribed to the mode coupling effects of spin fluctuations.


Ultralow-energy magnon anomaly in yttrium iron garnet

社本 真一; 安井 幸夫*; 松浦 直人*; 赤津 光洋*; 小林 義明*; 根本 祐一*; 家田 淳一

Physical Review Research (Internet), 2(3), p.033235_1 - 033235_6, 2020/08



Status of neutron spectrometers at J-PARC

梶本 亮一; 横尾 哲也*; 中村 充孝; 川北 至信; 松浦 直人*; 遠藤 仁*; 瀬戸 秀紀*; 伊藤 晋一*; 中島 健次; 河村 聖子

Physica B; Condensed Matter, 562, p.148 - 154, 2019/06


 被引用回数:5 パーセンタイル:48.71(Physics, Condensed Matter)

Seven time-of-flight quasielastic/inelastic neutron scattering instruments are installed on six beamlines in the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (JPARC). Four of these instruments are chopper-type direct-geometry spectrometers, one is a near-backscattering indirect-geometry spectrometer, and the other two are spin-echo-type spectrometers. This paper reviews the characteristic features, recent scientific outcomes, and progress in development of MLF spectrometers.


Proceedings of the User Group Meeting on MLF Spectrometers (DIRECTION 2018); October 11, 2018, Ibaraki Quantum Beam Research Center (Tokai, Ibaraki, Japan)

梶本 亮一; 横尾 哲也*; 松浦 直人*

JAEA-Review 2018-024, 78 Pages, 2019/01


平成30年10月11日、MLF中性子分光器による合同のユーザーミーティング「DIRECTION 2018」がJ-PARC MLF、高エネルギー加速器研究機構物質構造科学研究所、総合科学研究機構の共催で開催された。本ミーティングは6つの分光器、すなわちBL01(4SEASONS)、BL02(DNA)、BL06(VIN ROSE)、BL12(HRC)、BL14(AMATERAS)、BL23(POLANO)におけるユーザー利用の活性化およびユーザーと装置の協力関係の構築を目指して開催されたものである。研究会では14件の口頭発表および21件のポスター発表が行われ、各装置を利用して行われた研究成果の紹介、各装置や試料環境に関する現状の報告がなされるとともに、装置や試料環境に関する要望や今後の展開等について密接な議論が交わされた。本報告書はこのミーティングの講演要旨および講演で使用された発表資料を収録したものである。


Neutron scattering study of yttrium iron garnet

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

 被引用回数:10 パーセンタイル:63.24(Materials Science, Multidisciplinary)



Polar rotor scattering as atomic-level origin of low mobility and thermal conductivity of perovskite CH$$_{3}$$NH$$_{3}$$PbI$$_{3}$$

Li, B.; 川北 至信; Liu, Y.*; Wang, M.*; 松浦 直人*; 柴田 薫; 河村 聖子; 山田 武*; Lin, S.*; 中島 健次; et al.

Nature Communications (Internet), 8, p.16086_1 - 16086_9, 2017/06

 被引用回数:52 パーセンタイル:91.93(Multidisciplinary Sciences)

Perovskite CH$$_{3}$$NH$$_{3}$$PbI$$_{3}$$ exhibits outstanding photovoltaic performances, but the understanding of the atomic motions remains inadequate even though they take a fundamental role in transport properties. Here, we present a complete atomic dynamic picture consisting of molecular jumping rotational modes and phonons, which is established by carrying out high-resolution time-of-flight quasi-elastic and inelastic neutron scattering measurements in a wide energy window ranging from 0.0036 to 54 meV on a large single crystal sample, respectively. The ultrafast orientational disorder of molecular dipoles, activated at approximately 165 K, acts as an additional scattering source for optical phonons as well as for charge carriers. It is revealed that acoustic phonons dominate the thermal transport, rather than optical phonons due to sub-picosecond lifetimes. These microscopic insights provide a solid standing point, on which perovskite solar cells can be understood more accurately and their performances are perhaps further optimized.


Development of spin-wave-like dispersive excitations below the pseudogap temperature in the high-temperature superconductor La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$

松浦 直人*; 川村 奨*; 藤田 全基*; 梶本 亮一; 山田 和芳*

Physical Review B, 95(2), p.024504_1 - 024504_6, 2017/01

 被引用回数:10 パーセンタイル:57.46(Materials Science, Multidisciplinary)

Inelastic neutron scattering measurements of magnetic excitations in hole-doped high-$$T_c$$ cuprates La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ ($$x = 0$$ and 0.075) have been performed over a wide temperature range of 5 $$sim$$ 500 K extending beyond the pseudogap temperature of $$sim$$360 K for $$x = 0.075$$. For $$x = 0$$, the two-dimensional spin-wave excitations at low temperatures are thermally robust and the dispersion is slightly softened on heating up to $$T = 400$$ K. For $$x = 0.075$$, the spin-wave-like excitations in the upper part of the hourglass-shaped dispersion remain at $$T = 300$$ K. However, further heating above $$T = 400$$ K induces a broad ridge centered at $$(1/2, 1/2)$$; thereby the hourglass-shaped dispersion becomes blurred above the pseudogap temperature. The localized spin nature of magnetic excitations below $$T^*$$ suggests that the pseudogap is related to a proximity to a Mott insulator rather than being a precursor of Cooper pairs.


Negative correlation between electrical response and domain size in a Ti-composition-gradient Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ crystal near the morphotropic phase boundary

清水 大輔*; 塚田 慎也*; 松浦 直人*; 坂本 潤哉*; 小島 誠治*; 並河 一道*; 水木 純一郎; 大和田 謙二

Physical Review B, 92(17), p.174121_1 - 174121_5, 2015/11

 被引用回数:10 パーセンタイル:48.83(Materials Science, Multidisciplinary)



Neutron scattering study of spin fluctuations in La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ by four-dimensional mapping of neutron cross-sections using the 4SEASONS chopper spectrometer

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 La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ (LSCO) by TOF measurements revealed that magnetic dynamical structure factor has a maximum at $$sim$$ 18 meV. To clarify the origin of the maximum, we carried out 4 dimensional mapping of dynamical structure factor $$S(Q, omega)$$ to see details of both magnons and phonons. We found that $$x$$ = 0 shows ordinary spin waves while $$x$$ = 0.08 shows a maximum at $$sim$$ 18 meV where $$Q$$-independent phonon branch crosses. This imply that in superconducting compositions phonon may also indirectly related to the superconductivity.


Temperature dependence of spin fluctuations in underdoped La$$_{1.90}$$Sr$$_{0.10}$$CuO$$_4$$

佐藤 研太朗*; 松浦 直人*; 藤田 全基*; 梶本 亮一; Ji, S.*; 池内 和彦*; 中村 充孝; 稲村 泰弘; 新井 正敏; 榎木 勝徳*; et al.

JPS Conference Proceedings (Internet), 3, p.017010_1 - 017010_6, 2014/06

We studied the temperature dependence of spin excitation in the underdoped La$$_{1.90}$$Sr$$_{0.10}$$CuO$$_{4}$$ in a wide energy range. At low temperature, a clear magnetic signal emerging from incommensurate (IC) (0.5$$pm$$0.09, 0.5) positions was observed. The low-energy ($$sim$$10 meV) IC signal was confirmed at 200K, while the IC signal gradually merges upon warming and turns into a single commensurate peak centered at (0.5, 0.5) at 300 K. The overall spectral shape above $$sim$$60 meV measured at 5 K and 350 K was almost the same, meaning the weak thermal effect on the high-energy dispersion relation. This weak change in the high-energy dispersion is consistent with the localized spin picture, whereas the robust IC structure against the temperature would be difficult to explain within a simple stripe model.


Damped soft phonons and diffuse scattering in (Bi$$_{1/2}$$Na$$_{1/2}$$)TiO$$_{3}$$

松浦 直人*; 飯田 裕之*; 廣田 和馬*; 大和田 謙二; 野口 祐二*; 宮山 勝*

Physical Review B, 87(6), p.064109_1 - 064109_10, 2013/02

 被引用回数:26 パーセンタイル:76.11(Materials Science, Multidisciplinary)



Ni-substitution effects on the spin dynamics and superconductivity in La$$_{1.85}$$Sr$$_{0.15}$$CuO$$_{4}$$

松浦 直人*; 藤田 全基*; 平賀 晴弘*; 古府 麻衣子*; 木村 宏之*; 脇本 秀一; Perring, T. G.*; Frost, C. D.*; 山田 和芳*

Physical Review B, 86(13), p.134529_1 - 134529_8, 2012/10

 被引用回数:6 パーセンタイル:31.07(Materials Science, Multidisciplinary)

Systematic inelastic neutron scattering studies have been performed on La$$_{1.85}$$Sr$$_{0.15}$$Cu$$_{1-y}$$Ni$$_{y}$$O$$_{4}$$ in order to elucidate the microscopic mechanism of magnetic Ni impurity doping effects on spin dynamics and superconductivity. In contrast to Zn doping, which precipitates static or quasistatic spin correlations around dopant, Ni doping remarkably reduces $$E_{rm comme}$$, the minimum energy of the upward branch of the hourglass-shaped magnetic dispersion where a commensurate magnetic peak is observed. Ni doping at $$y sim 0.04$$ further reduces $$E_{rm comme}$$ to zero energy and broadens the distribution of $$E_{rm comme}$$, corresponding to the appearance of the normal state at base temperature ($$T sim 4$$ K) as well as the broadening of the superconducting transition.


東海再処理施設周辺の環境放射線モニタリング結果; 2009年度

住谷 秀一; 松浦 賢一; 渡辺 均; 中野 政尚; 竹安 正則; 藤田 博喜; 磯崎 徳重; 森澤 正人; 水谷 朋子; 國分 祐司; et al.

JAEA-Review 2011-004, 161 Pages, 2011/03




Magnetic and superconducting properties of CeRhGe$$_2$$ and CePtSi$$_2$$

広瀬 雄介*; 西村 尚人*; 本多 史憲*; 杉山 清寛*; 萩原 政幸*; 金道 浩一*; 竹内 徹也*; 山本 悦嗣; 芳賀 芳範; 松浦 直人*; et al.

Journal of the Physical Society of Japan, 80(2), p.024711_1 - 024711_12, 2011/02

 被引用回数:6 パーセンタイル:46.09(Physics, Multidisciplinary)

Magnetic and superconducting properties of CeRhGe$$_2$$ and CePtSI$$_2$$ have been investigated by bulk property measurements and neutron scattering experiments. CeRhGe$$_2$$ was found to order antiferromagnetically with an ordered moment 1.3 $$mu_{rm B}$$/Ce along the $$c$$-axis of the orthorhombic unit cell. High pressure resistivity measurements revealed a suppression of the antiferromagnetic transition with increasing pressure and the occurrence of superconductivity near the critical pressure where antiferromagnetism vanishes. Quantum-critical characteristics are expected to these compounds.



住谷 秀一; 松浦 賢一; 中野 政尚; 竹安 正則; 森澤 正人; 小沼 利光; 藤田 博喜; 水谷 朋子; 渡辺 一*; 菅井 将光*

JAEA-Review 2009-064, 166 Pages, 2010/03


日本原子力研究開発機構東海研究開発センター核燃料サイクル工学研究所では、再処理施設保安規定に定める環境放射能監視計画及び海洋環境放射能監視計画並びに茨城県東海地区環境放射線監視委員会の定める環境放射線監視計画に基づき、再処理施設周辺の環境放射線及び放射能の監視を行っている。また、研究所あるいは周辺事業所において事故等が発生したときは緊急時モニタリングを実施するため、原子力災害対策特別措置法に基づく放射線監視設備及び原子力防災資機材等を整備している。本マニュアルは、放射線管理部環境監視課が所掌するおもに陸上環境監視業務に使用する(1)放射線(能)監視設備、(2)気象観測設備、(3)データ収集処理システムの機器構成及び取り扱い等について取りまとめたものであり、1979年6月の制定以来、保安規定及び環境監視計画等の変更に伴い、1980年5月及び1983年12月の追加・改訂、1993年2月の全面改訂(PNC TN8520 93-001)を経て運用されてきた。前回改訂から16年が経過し、設備・機器の一部が更新されたこと、2001年の原子力災害対策特別措置法施行後、同法に基づき放射線監視設備及び原子力防災資機材等が整備されたことを踏まえ、記載項目全般について見直し、改訂を行った。


東海再処理施設周辺の環境放射線モニタリング結果; 2008年度

武石 稔; 住谷 秀一; 松浦 賢一; 渡辺 均; 中野 政尚; 竹安 正則; 磯崎 久明*; 磯崎 徳重; 森澤 正人; 藤田 博喜; et al.

JAEA-Review 2009-048, 177 Pages, 2009/12


核燃料サイクル工学研究所では、「日本原子力研究開発機構東海研究開発センター核燃料サイクル工学研究所再処理施設保安規定、第IV編 環境監視」に基づき、再処理施設周辺の環境放射線モニタリングを実施している。本報告書は、2008年4月から2009年3月までの間に実施した環境モニタリングの結果、及び大気,海洋への放射性物質の放出に起因する周辺公衆の線量算出結果について、取りまとめたものである。なお、環境監視計画の概要、測定方法の概要、測定結果及びその経時変化、気象統計結果、放射性廃棄物の放出状況の内訳等については付録として収録した。

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