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論文

Speciation of cesium in a radiocesium-bearing microparticle emitted from Unit 1 during the Fukushima nuclear accident by XANES spectroscopy using transition edge sensor

高橋嘉夫*; 三浦輝*; 山田真也*; 関澤央輝*; 新田清文*; 橋本直*; 蓬田匠; 山口瑛子; 岡田信二*; 板井啓明*; et al.

Journal of Hazardous Materials, 495, p.139031_1 - 139031_19, 2025/09

https://doi.org/10.1016/j.jhazmat.2025.139031

本発表では、2011年の福島第一原子力発電所事故で放出された放射性セシウム含有微粒子(CsMP)中のセシウムの化学状態を、高分解能X線吸収分光法(XANES)とマイクロX線蛍光(-XRF)を用いて解析した。その結果、主にガラス中に溶解したセシウムと、内部空隙表面に濃縮したセシウムの2種が確認された。後者はもともと気体として存在し、溶けたガラスが冷えて固まる際に濃縮したと考えられる。これらの知見は、事故時のCsMP形成過程や今後の廃炉作業、安全評価に重要である。

論文

Effects of the hydration states of water molecules on the mechanical properties of dual movable cross-linked polymeric gels

河合優作*; Park, J.*; 元川竜平; 以倉崚平*; 村山駿介*; 山岡賢司*; 藤井義久*; 池本夕佳*; 田中賢*; 松葉豪*; et al.

ACS Applied Polymer Materials (Internet), 7(12), p.7767 - 7776, 2025/06

https://doi.org/10.1021/acsapm.5c00270

The material properties of polymeric materials in aqueous environments are significantly influenced by water content. It is widely recognized that polymeric materials become more brittle with increased water content. However, the specific relationship between hydration levels and polymer chains has not been fully elucidated, leaving many uncertainties. Conversely, intermediate water (IMW), which refers to adsorbed water, plays an active role in influencing the biocompatibility and antifouling properties of these materials. In this study, we examined the correlation between IMW and toughness (Gf) / Youngs modulus (E). We synthesized dual cross-network (DC) elastomers through the bulk copolymerization of cyclodextrin (CD) monomers and vinyl monomers in the presence of movable cross-linked elastomers. The resulting DC elastomers exhibited both high Gf and high E. We used poly(2-methoxyethyl acrylate) (PMEA) as the primary polymer and poly(N,N-dimethyl acrylamide) (PDMAA) as the secondary polymer. The DC materials were formulated as DC(MEA-DMAA)(100-w:w)(Wc), where w and Wc represent the weight percentage of the secondary polymer (PDMAA) and the water content, respectively. The mechanical properties of the DC materials mostly decreased with increasing amounts of the secondary polymer. However, DC(MEA-DMAA)(90:10)(22), which contained 10 wt percent of PDMAA, exhibited the highest Gf and E among all samples. Differential scanning calorimetry (DSC) measurements indicated the presence of IMW in DC(MEA-DMAA)(90:10)(22). We propose that the IMW in this sample facilitates the formation of crosslinks between polymer chains and water molecules, contributing to the observed enhancements in E and Gf.

論文

Neutron reflectivity study on the adsorption layer of polyethylene grown on Si substrate

下北啓輔*; 山本勝宏*; 宮田登*; 柴田基樹*; 中西洋平*; 荒川勝利*; 竹中幹人*; 木田拓充*; 徳満勝久*; 田中亮*; et al.

Langmuir, 40(30), p.15758 - 15766, 2024/07

https://doi.org/10.1021/acs.langmuir.4c01584

被引用回数：2 パーセンタイル：43.35(Chemistry, Multidisciplinary)

To investigate the structure of the interface between polyethylene films and substrates, the neutron reflectivity (NR) of deuterated polyethylene (dPE) thin films deposited on Si substrates was measured, demonstrating water accumulation at the interface, even under ambient conditions. After leaching the thermally annealed dPE films in hot p-xylene, NR measurements were conducted on the layers remaining on the substrate, clearly revealing that the adsorption layer of dPE grew during annealing and consisted of two layers, an inner adsorption layer and an outer adsorption layer, as previously proposed for amorphous polymers. The inner adsorption layer was approximately 3.7 nm thick with a density comparable to that of the bulk. The outer adsorption layer was several nanometers thick and appeared to grow insufficiently on top of the inner adsorption layer under the annealing conditions examined in this study. This study clarifying the growth of the adsorption layer of polyethylene at the interface with an inorganic substrate is useful for improving the performance of polymer/inorganic filler nanocomposites due to the wide utility of crystalline polyolefins as polymer matrix materials in nanocomposites.

論文

Observation of high-pressure polymorphs in bulk silicon formed at relativistic laser intensities

Rapp, L.*; 松岡健之*; Firestein, K. L.*; 寒河江大輔*; 羽原英明*; 向井啓一郎*; 田中和夫*; Gamaly, E. G.*; 兒玉了祐*; 瀬戸雄介*; et al.

Physical Review Research (Internet), 6(2), p.023101_1 - 023101_18, 2024/04

https://doi.org/10.1103/PhysRevResearch.6.023101

固体表面に超相対論的強度のレーザーパルスを照射すると表面にプラズマが発生し、内部は超高圧状態になることが知られている。本研究ではシリコン単結晶に当該レーザーを照射し、内部に生成された高圧相の結晶構造分析をBL22XU(JAEA-BL)の応力・イメージングステーションの回折システムにより実施した。その結果、内部には体心、菱面体、六方晶、正方晶というシリコンが持つといわれている高圧相の存在が確認された。今後は、さらにデータの蓄積を図り、材料内部の構造、強度、機能性制御への発展を図っていきたいと考えている。

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：1 パーセンタイル：6.56(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

Microbial influences on manganese deposit formation at Yunotaki Fall, Japan

白石史人*; 千原亮二*; 谷本理沙*; 田中万也; 高橋嘉夫*

Island Arc, 31(1), p.e12448_1 - e12448_9, 2022/05

https://doi.org/10.1111/iar.12448

被引用回数：0 パーセンタイル：0.00(Geosciences, Multidisciplinary)

北海道オンネトー湯の滝では、藻類が光合成により放出する酸素がマンガン酸化細菌によるマンガン酸化物形成を支えていると考えられてきた。しかし、実際にこうした光合成由来の酸素がマンガン酸化物形成にどの程度寄与しているのかは不明であった。本研究では、こうした藻類由来の酸素がマンガン酸化物形成に与える影響について微小電極を用いた局所化学分析、バルク分析、DNA解析を組み合わせて調べた。その結果、オンネトー湯の滝では光合成由来酸素の寄与ははっきりせず、マンガン酸化細菌による直接的なマンガン酸化物形成が支配的であることが分かった。

論文

プルトニウムの体外排出に向けたキレート剤による除染に関する基礎検討; X線吸収分光法によるプルトニウム模擬元素とキレート剤との結合性評価

上原章寛*; Shuhui, X.*; 佐藤遼太朗*; 松村大樹; 辻卓也; 薬丸晴子*; 城鮎美*; 齋藤寛之*; 田中泉*; 石原弘*; et al.

X線分析の進歩,53, p.223 - 229, 2022/03

体内にアクチニドなどの放射性物質が取り込まれると、生体内配位子がアクチニドと化合物を生成し、体内滞留の原因となりうる。本研究では、アクチニドを体外に排出させるためのキレート剤の結合性評価を行うため、キレート剤と結合した元素の局所構造をX線吸収分光法によって解析し結合力を評価した。プルトニウム模擬元素としてジルコニウム(Zr),キレート剤として、EHBP(1-hydroxyethylidene-1,1-diphosphonate)およびDTPA (diethylenetriaminepentaacetate)を用いた。ZrはEHBPと八面体構造の錯体を形成するとともに、Zr-EHBP錯体はZr-DTPA錯体より強い結合を有することが分かった。これらの知見は、放射性元素による内部被ばく線量評価や、放射性元素を体外に取り除くための適切な除染方法の提案につながる。

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：8.82(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

Structures of magnetic excitations in the spin- $frac{1}{2}$ kagome-lattice antiferromagnets Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ and Rb $_{2}$ Cu $_{3}$ SnF $_{12}$

齋藤睦己*; 高岸龍之介*; 栗田伸之*; 渡邊正理*; 田中秀数*; 野村竜司*; 福元好志*; 池内和彦*; 梶本亮一

Physical Review B, 105(6), p.064424_1 - 064424_15, 2022/02

https://doi.org/10.1103/PhysRevB.105.064424

被引用回数：7 パーセンタイル：52.43(Materials Science, Multidisciplinary)

Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ is a spin- $frac{1}{2}$ antiferromagnet on a nearly uniform kagome lattice. This compound undergoes magnetic ordering with the = 0 structure and positive chirality, which is mainly caused by the large Dzyaloshinskii-Moriya interaction. Rb $_{2}$ Cu $_{3}$ SnF $_{12}$ is a spin- $frac{1}{2}$ antiferromagnet on a modified kagome lattice with a enlarged chemical unit cell at room temperature. Its ground state is a pinwheel valence bond solid (VBS) with an excitation gap. Here, we show the structures of magnetic excitations in Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ and Rb $_{2}$ Cu $_{3}$ SnF $_{12}$ investigated by inelastic neutron scattering in wide energy and momentum ranges. For Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ , four single-magnon excitation modes were observed. It was confirmed that the energy of single-magnon excitations arising from the point in the extended Brillouin zones is largely renormalized downwards. It was found that the broad excitation continuum without a marked structure spreads in a wide energy range from to approximately . These findings strongly suggest spinon excitations as elementary excitations in Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ . In Rb $_{2}$ Cu $_{3}$ SnF $_{12}$ , singlet-triplet excitations from the pinwheel VBS state and their ghost modes caused by the enlargement of the chemical unit cell were clearly confirmed. It was found that the excitation continuum is structured in the low-energy region approximately below $J_mathrm{avg}$ and the almost structureless high-energy excitation continuum extends to approximately $2.6J_mathrm{avg}$ . The characteristics of the high-energy excitation continuum are common to both Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ and Rb $_{2}$ Cu $_{3}$ SnF $_{12}$ , irrespective of their ground states. The experimental results strongly suggest that the spin liquid component remains in the ground state as quantum fluctuations in Cs $_{2}$ Cu $_{3}$ SnF $_{12}$ and Rb $_{2}$ Cu $_{3}$ SnF $_{12}$ .

論文

Absence of ferromagnetism in MnBiTe/BiTe down to 6 K

深澤拓朗*; 日下翔太郎*; 角田一樹; 橋爪瑞葵*; 一ノ倉聖*; 竹田幸治; 出田真一郎*; 田中清尚*; 清水亮太*; 一杉太郎*; et al.

Physical Review B, 103(20), p.205405_1 - 205405_6, 2021/05

https://doi.org/10.1103/PhysRevB.103.205405

被引用回数：12 パーセンタイル：57.03(Materials Science, Multidisciplinary)

We successfully fabricated a MnBiTe/BiTe heterostructure by incorporating Mn and Te inside the topmost quintuple layer of BiTe, as unambiguously confirmed by LEED I-V scanning transmission electron microscopy measurements. The surface-state Dirac cone of the heterostructure showed little change compared to that of the pristine BiTe and X-ray magnetic circular dichroism measurements showed that the system was paramagnetic down to 5.6 K. These results are in contrast to the previous works on related materials that showed magnetic order around 10 K as well as theoretical predictions and suggests the intricacy of the magnetic properties of two-dimensional van der Waals magnets.

論文

Stochastic estimation of radionuclide composition in wastes generated at Fukushima Daiichi Nuclear Power Station using Bayesian inference

杉山大輔*; 中林亮*; 田中真悟*; 駒義和; 高畠容子

Journal of Nuclear Science and Technology, 58(4), p.493 - 506, 2021/04

https://doi.org/10.1080/00223131.2021.1884137

被引用回数：3 パーセンタイル：27.71(Nuclear Science & Technology)

A modeling calculation methodology for estimating the radionuclide composition in the wastes generated at the Fukushima Daiichi nuclear power station has been upgraded by introducing an approach using Bayesian inference. The developed stochastic method describes the credible interval of the regression curve for the log-normal distribution of the measured transport ratio, which is used to calibrate the radionuclide transport parameters included in the modeling calculation. Consequently, the method can predict the robability distribution of the radionuclide composition in the Fukushima Daiichi wastes. The notable feature of the developed method is that it can explicitly investigate the improvement in the accuracy and confidence (degree of belief) of the estimation of the waste inventory using Bayesian inference. Specifically, the developed method can update and improve the degree of belief of the estimation of the radionuclide composition by visualizing the reduction in the width of uncertainty in the radionuclide transport parameters in the modeling calculation in accordance with the accumulation of analytically measured data. Further investigation is expected to improve the credibility of waste inventory estimation through iteration between modeling calculations and analytical measurements and to reduce excessive conservativeness in the estimated waste inventory dataset.

論文

Identification of hydrogen species on Pt/Al $_{2}$ O $_{3}$ by inelastic neutron scattering and their reactivity with ethylene

山添誠司*; 山本旭*; 細川三郎*; 福田良一*; 原賢二*; 中村充孝; 蒲沢和也*; 佃達哉*; 吉田寿雄*; 田中庸裕*

Catalysis Science & Technology, 11(1), p.116 - 123, 2021/01

https://doi.org/10.1039/D0CY01968B

被引用回数：8 パーセンタイル：23.08(Chemistry, Physical)

Hydrogen (H) species adsorbed on catalyst surfaces are key intermediates in catalytic hydrogenation reactions over supported metal catalysts. However, individual identification of H species on the metal catalysts has not been established to date. Here, we elucidated the H species on Pt/Al $_{2}$ O $_{3}$ by the combination of inelastic neutron scattering (INS) and density functional theory (DFT). Several H species in the presence of H $_{2}$ were successfully identified at different sites on the Pt surface and Al $_{2}$ O $_{3}$ support. The INS and FT-IR measurements revealed that the hydride/atop Pt-H, bridged perimeter/terrace Pt-H-Pt, and threefold Pt $_{3}$ -H are active intermediates in the C $_{2}$ H $_{4}$ hydrogenation reaction, whereas the edge Pt-H-Pt is a rather inert species. In addition, the measurements indicate that the Al $_{2}$ O $_{3}$ itself acts as hydrogen storage material by mediating AlO-H and Al-H-Al species, which serve H species in the C $_{2}$ H $_{4}$ hydrogenation reaction.

論文

France-Japan synthesis concept on sodium-cooled fast reactor review of a joint collaborative work

Rodriguez, G.*; Varaine, F.*; Costes, L.*; Venard, C.*; Serre, F.*; Chanteclair, F.*; Chenaud, M.-S.*; Dechelette, F.*; Hourcade, E.*; Plancq, D.*; et al.

EPJ Nuclear Sciences & Technologies (Internet), 7, p.15_1 - 15_8, 2021/00

https://doi.org/10.1051/epjn/2021014

フランス(CEAおよびFRAMATOME)と日本(原子力機構、三菱重工業および三菱FBRシステムズ)は、ナトリウム冷却高速炉の概念に関する共通の技術的知見を確立するための研究開発協力を実施した。これは、フランス/日本の両方で利用し得る実現可能な共通の設計コンセプトを開発する方法について日仏共同で検討を進めたものである。本論文は、これらナトリウム冷却高速炉の設計コンセプトに関する共同設計検討の概要をまとめたものである。

論文

Precious metal separations

成田弘一*; 粕谷亮*; 鈴木智也*; 元川竜平; 田中幹也*

Encyclopedia of Inorganic and Bioinorganic Chemistry (Internet), 28 Pages, 2020/12

https://doi.org/10.1002/9781119951438.eibc2756

The increasing use of precious metals (PMs) in industrial products such as electronics and catalysts has been increasingly important in PM separations. Most of PM separation and purification processes are performed using acidic chloride solutions; therefore, understanding of chemical properties and separation mechanisms of PM chloridometalates in solution is of key importance for improving the processes. This article focuses on solvent extraction of PMs from acidic chloride solutions as the main technology for the mutual separation of PMs and extensively covers the classical and modern methods. In addition, leaching methods, dominant species in acidic chloride solutions, and non-solvent extraction separation methods are also described.

論文

Flux growth and magnetic properties of helimagnetic hexagonal ferrite Ba(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ single crystals

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

https://doi.org/10.1021/acsomega.0c03671

被引用回数：5 パーセンタイル：18.13(Chemistry, Multidisciplinary)

六方晶フェライトBa(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ 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、Na $_{2}$ O-Fe $_{2}$ O $_{3}$ 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(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ 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(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ 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(Fe $_{1-x}$ Sc $_{x}$ ) $_{12}$ O $_{19}$ がヘリ磁性物質であることが確認された。

論文

Devil's staircase transition of the electronic structures in CeSb

黒田健太*; 新井陽介*; Rezaei, N.*; 國定聡*; 櫻木俊輔*; Alaei, M.*; 木下雄斗*; Bareille, C.*; 野口亮*; 中山充大*; et al.

Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06

https://doi.org/10.1038/s41467-020-16707-6

被引用回数：39 パーセンタイル：82.98(Multidisciplinary Sciences)

Solids with competing interactions often undergo complex phase transitions. Among them, CeSb is the most famous material where a number of the distinct magnetic phases called devil's staircase appear. We observed the electronic structure evolution across the devil's staircase transitions using bulk-sensitive angle-resolved photoemission spectroscopy.

論文

Sequestration and oxidation of Cr(III) by fungal Mn oxides with Mn(II) oxidizing activity

鈴木竜平*; 谷幸則*; 内藤博敬*; 宮田直幸*; 田中万也

Catalysts, 10(1), p.44_1 - 44_15, 2020/01

https://doi.org/10.3390/catal10010044

被引用回数：12 パーセンタイル：33.97(Chemistry, Physical)

本研究では、マンガン酸化菌KR21-2株を用いて形成させたマンガン酸化物に対してpH6のCr(NO $_{3}$ ) $_{3}$ 水溶液を用いて一回もしくは繰り返し処理を行った。好気条件においてはマンガン酸化物によるCr(III)のCr(VI)への酸化が認められた。この際、Mn(IV)がMn(II)に一旦還元されるものの真菌の活性のためMn(II)の再酸化により溶液中ではマンガンは検出されなかった。一方、嫌気条件においてはCr(III)の酸化は反応の初期段階で停止し、Mn(II)の再酸化が起こらないため還元されたマンガンが溶液中で検出された。

論文

Multi-step magnetic transitions in EuNiIn

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

https://doi.org/10.7566/JPSJ.89.014707

被引用回数：2 パーセンタイル：16.72(Physics, Multidisciplinary)

Magnetism in EuNiIn has been studied by specific heat, magnetic susceptibility, magnetization, $^{151}$ Eu Mssbauer spectroscopy, and neutron diffraction experiments. The specific heat shows two magnetic transitions at $T_{rm N1}$ and $T_{rm N2}$ 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 $T_{rm N2}$ . The magnetization curve along the b-axis at 2 K shows four successive magnetic field-induced transitions up to 50 kOe and, reaches 7 ${mu}_{rm B}$ /f.u. above 190 kOe, The magnetic phase diagram in EuNiIn has unique characteristics with five magnetic states in low magnetic field.

論文

Experimental investigation of the suppressed superconducting gap and double-resonance mode in Ba $_{1-x}$ K $_{x}$ Fe $_{2}$ As $_{2}$

出田真一郎*; 村井直樹; 中島正道*; 梶本亮一; 田中清尚*

Physical Review B, 100(23), p.235135_1 - 235135_7, 2019/12

https://doi.org/10.1103/PhysRevB.100.235135

被引用回数：3 パーセンタイル：12.45(Materials Science, Multidisciplinary)

Ba $_{1-x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ has an exotic physical property where that the C $_{2}$ -SDW phase suddenly changes to the C $_{4}$ -magnetic phase and superconductivity is suppressed within a narrow composition range around x = 0.25. We have investigated the doping dependence of the electronic structure of Ba $_{1-x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ using angle-resolved photoemission spectroscopy (ARPES) and found an anomaly in the superconducting (SC) gap structure only for x = 0.25 in both the hole and electron Fermi surfaces (FSs). We also propose that the mechanism of a newly observed double-resonance peak by inelastic neutron scattering is understandable by the SC gap obtained by ARPES. Our discovery reveals the important relationship between the C $_{4}$ - magnetic phase and superconductivity, and provides an opportunity to survey the underlying relationship between the SC gap and resonance mode in the hole-doped iron-based superconductor.

論文

A New approach for measuring the muon anomalous magnetic moment and electric dipole moment

阿部充志*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05

https://doi.org/10.1093/ptep/ptz030

被引用回数：167 パーセンタイル：99.37(Physics, Multidisciplinary)

この論文はJ-PARCにおける、ミューオン異常磁気モーメント $a_{mu}=(g-2)/2$ と電気双極子モーメント(EDM) $d_{mu}$ を測定する新しいアプローチを紹介する。我々の実験のゴールは、これまでと独立の、1/10の運動量と1/20のストレージリングを用いて、 $a_{mu}$ と $d_{mu}$ をこれまでにない精密な磁場で測定することである。さらに過去の実験との顕著な違いは、1/1000の横エミッタンスミューオンビーム(サーマルミューオンビーム)を用い、効率的なソレノイドへ縦入射し、ミューオンからの崩壊陽電子をトラッキングし、その小さな運動量ベクトルを求める点である。 $a_{mu}$ は統計精度450ppb、系統誤差70ppb、EDMについては $1.5times10^{-21}$ ecmの精度で測定することを目標とする。