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上田 祐生; Micheau, C.; 阿久津 和宏*; 徳永 紘平; 山田 雅子*; 山田 悟史*; Bourgeois, D.*; 元川 竜平
Langmuir, 40(46), p.24257 - 24271, 2024/11
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)本研究では、パーフルオロヘキサン中のフルオラスリン酸エステル(TFP)からなるフルオラス抽出系において、n-ヘキサン中の有機リン酸エステル(THP)からなる類似の有機抽出系と比較して、より高い金属イオン抽出性能に寄与する主要因を分子レベルで理解するために、硝酸溶液からのZr(IV)イオンの抽出の巨視的挙動を微視的構造情報と相関させた。拡張X線吸収微細構造、中性子反射率測定、中性子小角散乱により、それぞれZr(IV)イオン周辺の局所配位構造、界面における抽出剤分子の蓄積、バルク抽出相における抽出剤分子の構造が明らかになった。その結果、いずれの抽出系においても、界面には抽出剤分子はあまり蓄積しなかった。フルオラス抽出系では、硝酸との接触により凝集体が形成され、Zr(IV)抽出後も残存した。一方、有機抽出系では、二量体のみが形成された。Zr(IV)イオン周辺の局所的な配位構造とバルク抽出相における抽出剤分子の構造の違いが、フルオラス抽出系における高いZr(IV)抽出性能に寄与していると推測している。特に、フルオラス相中のZr(IV)濃度が増加しても凝集体の大きさはほとんど変化せず、これはフルオラス抽出系で相分離が起こらないことと密接に関係していると考えられる。
Gd
Mn
O
石井 裕太*; 坂倉 輝俊*; 石川 喜久*; 鬼柳 亮嗣; Lustikova, J.*; 青山 拓也*; 大串 研也*; 若林 裕助*; 木村 宏之*; 野田 幸男*
Physical Review B, 110(18), p.184404_1 - 184404_7, 2024/11
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Neutron-scattering measurements were employed to investigate the magnetic ordering in Tb
Gd
MnO (x = 0.485) enriched with the 
Gd isotope, a member of multiferroic RMnO (R = rare-earth element) compounds. This material, at low temperatures, exhibits commensurate magnetic (CM) ordering, which drives electric polarization. Notably, electric polarization diminishes as the temperature decreases further, while the CM ordering persists. Magnetic structure analyses revealed that a cycloidal magnetic structure along the c axis transforms into a sinusoidal-like structure, resulting in the nonferroelectric phase, whereas a collinear magnetic structure in the ab plane exhibits no significant change. The findings suggest that the cycloidal magnetic structure plays a key role in inducing electric polarization in the CM ordering of the present material.
松浦 直人*; Zhang, J.*; 上村 祥史*; 古府 麻衣子; 枝川 圭一*
Physical Review Letters, 133(13), p.136101_1 - 136101_5, 2024/09
被引用回数：1 パーセンタイル：48.32(Physics, Multidisciplinary)In quasicrystals lacking translational symmetry but having highly ordered structures, understanding how phonons propagate in their aperiodic lattices remains an unsolved issue. We present an inelastic neutron scattering study on acoustic phonon modes of icosahedral quasicrystal AlPdMn, revealing hierarchical pseudo-gap structure in low-energy acoustic modes. Additionally, phonon intensities are asymmetric in energy and wave vectors with respect to the Bragg peak, indicating characteristic nonreciprocal phonon propagation in quasicrystals.
Micheau, C.; 上田 祐生; 元川 竜平; 阿久津 和宏*; 山田 悟史*; 山田 雅子*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.
Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05
被引用回数：2 パーセンタイル：65.57(Chemistry, Physical)Supramolecular organization of amphiphilic extractant molecules is involved in metal cation selectivity and separation kinetics during solvent extraction. The relationship between extractant associates/aggregates formed in the organic bulk phase and at the liquid-liquid interface is poorly understood even though it affects the extraction mechanism. The nanoscopic structures of the extraction systems N,N,N',N'-tetrahexylmalonamide (THMA) in toluene and N,N'-dibutyl-N,N'-dimethyl-2-tetradecylmalonamide (DBMA) in n-heptane, used for either Pd(II) or Nd(III) selective extraction from an acidic aqueous phase, were examined. These systems present markedly different affinity for Pd(II) and Nd(III), and extraction kinetics. Extractant organization in the organic bulk phase and at the interface were compared by small-angle X-ray scattering, interfacial tension, and neutron reflectivity. THMA in toluene forms small associates in the organic bulk phase and accumulates in a diffuse layer at the interface, decreasing Pd(II) coordination probability and resulting in slow extraction. DBMA in n-heptane forms large aggregates and a compact, dense interfacial layer, resulting in rapid Pd(II) and Nd(III) extraction. Thus, Pd(II) extraction is driven by interfacial coordination alone, whereas the incorporation of Nd(III) into the core of large aggregates governs Nd(III) extraction in the interfacial layer. These results suggest that the interface should be described as a nanoscale interphase containing a high extractant concentration compared with the organic bulk phase.
complex exhibiting intermolecular proton shifting coupled spin transitionJi, T.*; Su, S.*; Wu, S.*; 堀 優太*; 重田 育照*; Huang, Y.*; Zheng, W.*; Xu, W.*; Zhang, X.*; 鬼柳 亮嗣; et al.
Angewandte Chemie; International Edition, 63(25), p.e202404843_1 - e202404843_6, 2024/04
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)In this study, we investigated reversible intermolecular proton shifting (IPS) coupled with spin transition (ST) in a novel Fe complex. The host Fe complex and the guest carboxylic acid anion were connected by intermolecular hydrogen bonds (IHBs). We extended the intramolecular proton transfer coupled ST phenomenon to the intermolecular system. The dynamic phenomenon was confirmed by variable-temperature single-crystal X-ray diffraction, neutron crystallography, and infrared spectroscopy.
樋口 雄紀*; 吉宗 航*; 加藤 悟*; 日比 章五*; 瀬戸山 大吾*; 伊勢川 和久*; 松本 吉弘*; 林田 洋寿*; 野崎 洋*; 原田 雅史*; et al.
Communications Engineering (Internet), 3, p.33_1 - 33_7, 2024/02
The automotive industry aims to ensure the cold-start capability of polymer electrolyte fuel cells (PEFCs) for developing fuel cell electric vehicles that can be driven in cold climates. Water and ice behavior is a key factor in maintaining this capability. Previously reported methods for visualizing water and/or ice are limited to small-sized PEFCs ( 
50 cm
), while fuel cell electric vehicles are equipped with larger PEFCs. Here, we developed a system using a pulsed spallation neutron beam to visualize water distribution and identify water/ice phases in practical-sized PEFCs at a cold start. The results show direct evidence of a stepwise freezing behavior inside the PEFC. The produced water initially accumulated at the center of the PEFC and then froze, followed by PEFC shutdown as freezing progressed. This study can serve as a reference to guide the development of cold-start protocols, cell design, and materials for next-generation fuel cell electric vehicles.
谷口 耕治*; Huang, P.-J.*; 佐賀山 基*; 鬼柳 亮嗣; 大石 一城*; 鬼頭 俊介*; 中村 唯我*; 宮坂 等*
Physical Review Materials (Internet), 8(2), p.024409_1 - 024409_10, 2024/02
被引用回数：2 パーセンタイル：56.91(Materials Science, Multidisciplinary)Leveraging the flexible material designability of organic-inorganic hybrid systems, spatial inversion symmetry breaking and spin-orbit coupling (SOC) were simultaneously controlled in a series of two-dimensional organic-inorganic hybrid perovskite (2D-OIHP) copper halides with ferromagnetic exchange interaction (FMI). In chiral molecule-incorporated 2D-OIHP copper halides, an increase in Br component over Cl component at halogen sites leads to systematic variations in magnetic phase diagrams owing to the competition between the FMI and Dzyaloshinskii-Moriya interaction induced by the SOC. The crucial role of noncentrosymmetry in the competition for the magnetic interactions was confirmed by comparing the magnetic phase diagrams of chiral and achiral 2D-OIHP copper bromides.
CoSi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 N
el 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.
古府 麻衣子; 河村 聖子; 村井 直樹; 石井 梨恵子*; 平井 大悟郎*; 有馬 寛*; 舟越 賢一*
Physical Review Research (Internet), 6(1), p.013006_1 - 013006_9, 2024/01
We revisited spin dynamics in archetypical classical spin glass systems, such as CuMn (
, 0.034, and 0.067) dilute alloys and iron aluminosilicate glass using a modern neutron scattering spectrometer with high neutron flux. The former is crystalline, and the latter is amorphous, where their spin glass state is well separated from magnetically ordered phases. Bose-scaled localized magnetic excitations were observed in both compounds below the spin-freezing temperature (
). The spectrum exhibits a maximum at low energy and a broad tail on the high-energy side. The excitation energy tends to be higher for the material with a higher . Above the , the spectrum considerably changes with temperature, thereby indicating the emergence of the magnetic relaxation process. The magnetic excitation in the spin glass state has much in common with the boson peak in structural glasses. We consider that the Bose-scaled broad excitation peak is an elementary excitation inherent in disordered systems.
Zhang, A.*; Deng, K.*; Sheng, J.*; Liu, P.*; Kumar, S.*; 島田 賢也*; Jiang, Z.*; Liu, Z.*; Shen, D.*; Li, J.*; et al.
Chinese Physics Letters, 40(12), p.126101_1 - 126101_8, 2023/12
被引用回数：11 パーセンタイル：83.08(Physics, Multidisciplinary)In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, itis predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral "Dirac-like" fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Here, by combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions.
野崎 洋*; 近藤 広規*; 篠原 武尚; 瀬戸山 大吾*; 松本 吉弘*; 佐々木 厳*; 伊勢川 和久*; 林田 洋寿*
Scientific Reports (Internet), 13, p.22082_1 - 22082_8, 2023/12
被引用回数：3 パーセンタイル：24.30(Multidisciplinary Sciences)Lithium ion batteries (LIBs) have become essential components that power most current technologies, thus making various safety evaluations necessary to ensure their safe use. Heating tests remain the most prominent source of safety issues. However, information on the phenomena occurring inside batteries during heating has remained inaccessible. In this study, we demonstrate the first in situ neutron imaging method to observe the internal structural deformation of LIBs during heating. We developed an airtight Al chamber specially designed to prevent radioactive contamination during in situ neutron imaging. We successfully observed the liquid electrolyte fluctuation inside a battery sample and the deformation of the protective plastic film upon heating up to thermal runaway.
柴田 基樹*; 中西 洋平*; 阿部 淳*; 有馬 寛*; 岩瀬 裕希*; 柴山 充弘*; 元川 竜平; 熊田 高之; 高田 慎一; 山本 勝宏*; et al.
Polymer Journal, 55(11), p.1165 - 1170, 2023/11
被引用回数：2 パーセンタイル：19.24(Polymer Science)Marine ecosystem degradation due to micro plastics is a significant environmental problem, as acknowledged by Sustainable Development Goal 14. Decomposition of plastics using near critical or supercritical water is one of the promising methods to reduce micro plastics. To attain the optimization of the method for improving environmental friendliness, it is necessary to clarify the structural change of materials during the process. We, thus, investigated the decomposition processes of polystyrene particles dispersed in deuterated water (DO) during heating under near critical or supercritical conditions by using in situ small-angle neutron scattering. Under subcritical conditions, the PS particles were swollen by DO due to increased compatibility with temperature. Near the critical point in subcritical conditions, the cleavage of PS chains in the particles occurred, so that the swollen ratio was much enhanced though the PS particles kept their shapes. In a supercritical condition, the PS particles were degraded into oil including oligomers or monomers and the phase-separated structures with styrene-rich and DO-rich regions.
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
被引用回数：5 パーセンタイル：51.73(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.
高木 寛貴*; 高木 里奈*; 見波 将*; 野本 拓也*; 大石 一城*; 鈴木 通人*; 柳 有起*; 平山 元昭*; Khanh, N.*; 軽部 皓介*; et al.
Nature Physics, 19(7), p.961 - 968, 2023/07
被引用回数：50 パーセンタイル：99.07(Physics, Multidisciplinary)In ferromagnets, electric current generally induces a transverse Hall voltage in proportion to the internal magnetization. This effect is frequently used for electrical readout of the spin up and down states. While these properties are usually not expected in antiferromagnets, recent theoretical studies predicted that non-coplanar antiferromagnetic order with finite scalar spin chirality - meaning a solid angle spanned by neighboring spins - can induce a large spontaneous Hall effect even without net magnetization or external magnetic field. This phenomenon, the spontaneous topological Hall effect, can potentially be used for the efficient electrical readout of the antiferromagnetic states, but it has not been experimentally verified due to a lack of appropriate materials hosting such magnetism. Here, we report the discovery of all-in-all-out type non-coplanar antiferromagnetic order in triangular lattice compounds CoTa
S
and CoNbS. These compounds are reported to host unconventionally large spontaneous Hall effect despite their vanishingly small net magnetization, and our analysis reveals that it can be explained in terms of the topological Hall effect that originates from the fictitious magnetic field associated with scalar spin chirality. These results indicate that the scalar spin chirality mechanism offers a promising route to the realisation of giant spontaneous Hall response even in compensated antiferromagnets, and highlight intercalated van der Waals magnets as a promising quasi-two-dimensional material platform to enable various nontrivial ways of electrical reading and possible writing of non-coplanar antiferromagnetic domains.
Sn
( = 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
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 .
Micheau, C.; 上田 祐生; 阿久津 和宏*; Bourgeois, D.*; 元川 竜平
Solvent Extraction and Ion Exchange, 41(2), p.221 - 240, 2023/02
被引用回数：4 パーセンタイル：43.72(Chemistry, Multidisciplinary)Malonamide derivatives, which are among the most extensively investigated extractants in solvent extraction of lanthanoids, actinides, and platinum group metal ions, were deuterated by using Pd/C and Rh/C catalysts with a DO/2-propanol mixture. This method enables to replace the hydrogen atoms by deuterium atoms in the malonamide chemical structure with a controllable deuteration rate. The maximum rate reaches 75 percent approximately, determined by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry. In addition, it has been demonstrated that extraction behavior of the malonamide molecules remains unchanged after the deuteration procedure. Deuterated malonamides should be a powerful tool for fundamental researches on solvent extraction systems, in particular, for structural analysis of the organic phases. The large difference in the neutron scattering cross-section between hydrogen and deuterium leads to a large difference in neutron scattering length density of the malonamide derivatives before and after the deuteration reaction. Therefore, using deuterated malonamides in small-angle neutron scattering and neutron reflectivity studies could give access to the nanoscopic structure of the specific solute species in the bulk organic phase and at the liquid-liquid interface, respectively. This deuteration method could become a general one and be extended to a wide variety of extractant molecules. In this way this work contributes to the development of the fundamental researches in solvent extraction systems.
田村 和久; 阿久津 和宏*; Cagnes, M.*; Darwish, T. A.*
ECS Advances (Internet), 1(2), p.020503_1 - 020503_5, 2022/06
中性子反射率測定によりイオン液体/Si電極界面の構造を調べた。部分的に重水素化した1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([BMIM]TFSA)を用いて、[BMIM]TFSA/Si(100)界面における、イオン液体分子の配向を調べた。実験結果は、負に帯電しているSi(100)電極表面では、電極表面に吸着しているイオン液体分子は、表面に平行に配向していることが分かった。
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
被引用回数：4 パーセンタイル：47.58(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 NHCl, 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.
橋本 俊輔*; 中島 健次; 菊地 龍弥*; 蒲沢 和也*; 柴田 薫; 山田 武*
Journal of Molecular Liquids, 342, p.117580_1 - 117580_8, 2021/11
被引用回数：4 パーセンタイル：24.04(Chemistry, Physical)エチレングリコール水溶液中に二酸化ケイ素(SiO)ナノ粒子を分散したナノ流体の準弾性中性子散乱測定(QENS)およびパルス磁場勾配核磁気共鳴分析(PFGNMR)を行った。研究目的は、このナノ流体の熱伝導率が理論値を超えて増加するメカニズムを解明することだった。得られた実験結果は、SiOナノ粒子の周りの液体分子の運動が非常に制限されているため、SiOナノ粒子の添加により、エチレングリコール水溶液中の液体分子の自己拡散係数が低下していることを示す。そして温度一定の条件で、SiOナノ流体中で、液体分子の自己拡散係数が減少するにつれて、熱伝導率が増加した。
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：8 パーセンタイル：58.52(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. Magnetization measurements demonstrate that an antiferromagnetic ordering occurs at = 2.3 K in the crystalline state, while a spin glass transition occurs at 
= 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 and gradually disappeared above . 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.
