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段野下 宙志*; 長谷川 寛*; 樋口 翔*; 松田 広志*; Gong, W.; 川崎 卓郎; Harjo, S.; 梅澤 修*
Scripta Materialia, 236, p.115648_1 - 115648_5, 2023/11
被引用回数：0Work-hardening behavior of a lath martensitic Fe-18Ni alloy during tensile deformation is discussed based on the Taylor's equation. The dislocation characteristics are monitored using in situ neutron diffraction. In the specimens of as-quenched (AQ) and tempered at 573 K (T573), the dislocations are extremely dense and randomly arranged. The dislocations in AQ and T573 form dislocation cells as deformation progresses. Consequently, a composite condition comprising cell walls and cell interiors is formed, and the coefficient 
in the Taylor's equation increases. Cells are already present in the specimen tempered at 773 K (T773), which has a low dislocation density and a large fraction of edge-type dislocations. As deformation continues, the dislocation density of T773 increases, its cell size decreases, and its composite condition become stronger. Simultaneously, the edge-type dislocation fraction decreases, keeping unchanged. Thus, both the dislocation arrangement and character affected , thereby affecting the work-hardening behavior.
reduction and salicylic acid decomposition杉田 剛; 森 勝伸*; 下山 巖
Applied Clay Science, 243, p.107074_1 - 107074_8, 2023/10
粘土鉱物のサブグループである黒雲母をCaCl
で熱処理することにより、光触媒に変換することを検討した。熱処理後に得られた反応生成物の組成,構造、および6価クロムとサリチル酸(SA)に対する光触媒活性を検討した。黒雲母とCaClの混合物を600
Cまで加熱すると黒雲母の結晶構造が保持され、700Cまで加熱すると黒雲母から八面体ワダライト結晶への相変態が起こった。単位表面積あたりの6価クロムの光触媒還元率およびSAの光触媒分解効率は、処理温度の上昇とともに大きく増加した。また、熱処理後に黒雲母構造を保持した試料でも一定の光触媒活性を示したことから、この方法は他の一般的な天然材料から光触媒を調製する場合にも適している可能性がある。
Mao, W.; Gao, S.*; Gong, W.; Bai, Y.*; Harjo, S.; Park, M.-H.*; 柴田 曉伸*; 辻 伸泰*
Acta Materialia, 256, p.119139_1 - 119139_16, 2023/09
被引用回数：0変形誘起塑性(TRIP)鋼は、変形誘起マルテンサイト変態(DIMT)に伴う加工硬化率の向上により、強度と延性の優れた組み合わせを示す。TRIP鋼や合金の加工硬化挙動におけるDIMTの役割を定量的に評価することは、強度と延性の両立を可能にする先進材料を設計するための指針を与えるが、変形中に相組成が変化し続け、応力と塑性ひずみの両方が構成相間で動的に分配されるため、その評価は困難である。本研究では、Fe-24Ni-0.3C(wt.%)TRIPオーステナイト鋼の引張変形とその場中性子回折測定を行った。中性子回折測定による応力分割と相分割に基づく解析手法を提案し、試験片の引張流動応力と加工硬化率を、オーステナイト母相,変形誘起マルテンサイト、DIMT変態速度に関連する因子に分解し、試料の加工硬化挙動における各因子の役割を考察した。さらに、回折プロファイル解析により測定した転位密度を用いてオーステナイトとマルテンサイト間の塑性ひずみ分配を間接的に推定し、材料中のオーステナイトとマルテンサイト間の応力・ひずみ分配の全体像を構築した。その結果、変形誘起マルテンサイト変態速度とマルテンサイトが負担する相応力の両方が、材料の全体的な引張特性に重要な役割を果たしていることが示唆された。提案した分解解析法は、TRIP現象を示す多相合金の機械的挙動を調べるために広く適用できる可能性がある。
Su, Y. H.; 及川 健一; 篠原 武尚; 甲斐 哲也; 堀野 孝*; 井戸原 修*; 三阪 佳孝*; 友田 陽*
International Journal of Fatigue, 174, p.107729_1 - 107729_12, 2023/09
被引用回数：1 パーセンタイル：0.01(Engineering, Mechanical)A novel procedure, double induction quenching (DIQ), effective for improving the fatigue strength of gear products, has been used for producing gears with steep gradients of compressive residual stress generated in the tooth surface. We performed a Bragg edge imaging experiment at a pulsed neutron source to determine the spatial distribution of the {110} lattice spacing (d
) and the broadening of the {110} Bragg edge (w) on the DIQ gear product after tooth-bending fatigue tests to which different loading cycles were applied. No significant difference occurred in the d and the wat Hofer 's critical section of the teeth with different loading conditions within the accuracy of data analysis. However, we detected a decrease in the w and changes in the residual lattice strain distribution in the axial direction along the tooth root directions at the opposite side of Hofer 's critical section for both teeth after 3
10 
and 810 cycles, relieving the compressive residual stresses during the fatigue process. The residual stress close to the gear tooth surface determined by X-ray diffraction using sequential polishing showed a slight relaxation and redistribution from the tensile side in the hoop direction, complementary to the neutron Bragg edge imaging.
solution in the gigapascal pressure range山口 敏男*; 福山 菜美*; 吉田 亨次*; 片山 芳則*; 町田 真一*; 服部 高典
Liquids, 3(3), p.288 - 302, 2023/09
圧力0.1MPaから4GPa、温度300Kから500Kにおける2mol/kg MgCl水溶液の構造をX線と中性子散乱測定によって明らかにした。この散乱データを経験的ポテンシャル構造精密化(EPSR)モデリングにより解析し、圧力と温度の関数としてペア分布関数、配位数分布、角度分布、空間密度関数を導出した。Mg
は第3殻まで広がったリジッドな溶媒和殻を形成している。つまり、0GPaで約6個の水分子を含む6配位八面体の第1溶媒和殻は、ギガパスカルの圧力領域では、近接イオン対を形成し、約5個の水分子と1個のCl
となる。また、Clの溶媒和も、圧力によって大きく変わる。つまり、Clイオンまわりの水分子の配位数は、0.1MPa/300Kでの8から、4GPa/500Kでの10に増加する。また溶媒(水)も、0.1MPa/300Kでの四面体ネットワーク構造から、ギガパスカルの圧力領域では、密に詰まった構造へと変化する。このとき、中心水分子1個まわりの隣接酸素原子数は、0.1MPa/298Kでの4.6個から4GPa/500Kでの8.4個へと徐々に増加する。
Mg and long-period stacking ordered phases in a Mg-Zn-Y alloy by hot-extrusion with low extrusion ratioHarjo, S.; Gong, W.; 相澤 一也; 川崎 卓郎; 山崎 倫昭*
Acta Materialia, 255, p.119029_1 - 119029_12, 2023/08
被引用回数：1 パーセンタイル：0.01(Materials Science, Multidisciplinary)An as-cast sample and two hot-extruded samples with different extrusion ratios (R) of Mg
Zn
Y alloy containing the HCP matrix (Mg) and the long-period stacking ordered phase (LPSO) of about 25-vol%, were used in tensile deformation in situ neutron diffraction experiments, to elucidate the effects of uniquely different microstructural evolutions in Mg and LPSO with varying the R value to the mechanical properties. Mg behaved as the soft phase and LPSO as the hard phase, and hot-extrusion improved the strength of both. At the R value of 5.0, a bimodal microstructure was created in Mg, increasing largely the yield strength of Mg. With increasing the R value to 12.5, the bimodal microstructure of Mg collapsed and the yield strength of Mg decreased. However, the strength of LPSO increased monotonously with increasing the R value due to the developments of kink bands and texture.
Sala, G.*; Stone, M. B.*; Hal
sz, G. B.*; Lumsden, M. D.*; Fay, A, F,*; Pajerowski, D. M.*; 河村 聖子; 金子 耕士; Mazzone, D. G.*; Simutis, G.*; et al.
Communications Physics (Internet), 6, p.234_1 - 234_7, 2023/08
We demonstrate and elucidate quantum effects on the honeycomb lattice through comprehensive inelastic neutron scattering measurements of the prototype honeycomb lattice quantum magnet YbCl
as a function of applied magnetic field. Examining the spectrum above the saturation field where linear spin-wave theory is essentially exact, we accurately determine the dominant nearest-neighbor Heisenberg interaction. Below the saturation field, we reveal a field-dependent energy renormalization of the entire magnetic spectrum; the sharp spin-wave modes as well as the multimagnon continuum. This renormalization is a quantum effect that can be accurately captured by the first 1=S correction in nonlinear spin-wave theory. Furthermore, we find that the application of a magnetic field induces a qualitatively new sharp feature inside the multimagnon continuum; the lower edge of a specific two-magnon component; which is complementary to the previously observed Van Hove singularity and demonstrates that structures within the multimagnon continuum can occur over a wide experimental parameter space and can be used as an additional means of identifying quantum phenomena.
関根 由莉奈
ファインケミカル, 52(8), p.25 - 32, 2023/08
凍結現象を利用することで、カルボキシメチルセルロースナノファイバーを主体とした無害な素材のみで 高い圧縮負荷にも耐えるハイドロゲルが形成することを発見した。鍵となるのは水溶液が凍結する時に起きる、氷結晶と溶質の相分離である。本稿では凍結架橋ゲルの形成メカニズムやゲルの特性について述べる。
前田 亮; 瀬川 麻里子; 藤 暢輔; 遠藤 駿典; 中村 詔司; 木村 敦
Journal of Radioanalytical and Nuclear Chemistry, 332(8), p.2995 - 2999, 2023/08
被引用回数：0 パーセンタイル：0.02(Chemistry, Analytical)The accuracy of the prompt 
-ray analysis is known to degrade for the samples containing neutron-scattering materials, such as hydrogen, depending on its content. Recently, we discovered that the density of the scattering materials also affects the accuracy. In this paper, we developed a correction method for the effect of the sample densities. The developed correction method is straightforward and applicable to samples with unknown densities. The simulation and experiments verified the performance of the correction method. The results confirmed that the correction method could reduce the uncertainty due to sample density from 47% to approximately 1%.
金子 耕士; 田端 千紘; 萩原 雅人; 山内 宏樹; 久保田 正人; 長壁 豊隆; 大貫 惇睦*
Journal of the Physical Society of Japan, 92(8), p.085001_1 - 085001_2, 2023/08
被引用回数：0 パーセンタイル：0.01(Physics, Multidisciplinary)A magnetic order in orthorhombic GdCu was investigated by a single crystal neutron diffraction with thermal neutron. Magnetic peaks were observed at incommensurate positions described by the ordering vector 
=(
~1~0) with =0.678 at 4~K. This ordering vector is close to the commensurate one with 
=(2/3~1~0) reported earlier, but clearly deviates. The incommensurate nature of the magnetic order in GdCu is further corroborated by the peak shift with temperature below 
.
-Mo
O
revealed by angle-resolved photoelectron spectroscopy and first-principles calculation角田 一樹; 檜垣 聡太*; 佐藤 仁*; 水流 大地*; 宮本 幸治*; 奥田 太一*; 黒岩 芳弘*; 森吉 千佳子*; 高瀬 浩一*; 小口 多美夫*; et al.
Journal of the Physical Society of Japan, 92(8), p.084706_1 - 084706_6, 2023/08
We investigated the electronic structure of -MoO bulk crystal in the whole Brillouin zone at a normal metallic state by utilizing resonant and angle-resolved photoelectron spectroscopies and first-principles calculations. Mo 4
-4
resonant photoelectron experiment revealed that the Mo 4 electrons of MoO
octahedra mainly contributed to the electrical conductivity. We also demonstrated that the free electron-like band dispersions along 
axis, consisting of Mo 4
electrons, do not show clear 
and 
dependences and formed a one-dimensional Fermi surface even at the normal state. The observed low-dimensional and anisotropic band structures are expected to induce exotic physical properties such as quantized bulk Hall effect, charge density wave transitions, and Luttinger liquid behavior.
竹田 幸治; Posp
il, J.*; 山上 浩志; 山本 悦嗣; 芳賀 芳範
Physical Review B, 108(8), p.085129_1 - 085129_10, 2023/08
We investigated the element-specific electronic states and magnetic properties of ferromagnetic superconductor UCoGe and Ru-substituted U(Co
Ru
)Ge using soft X-ray magnetic circular dichroism (XMCD) experiments. YCoGe, a nonmagnetic compound without the 5
electrons, was also examined as a reference material. The shapes of the XMCD spectra of UCoGe at the U 
and Ge 
edges are indistinguishably similar to those of U(CoRu)Ge. On the other hand, the XMCD spectral shape at the Co 
edge is very peculiar and is changed by the existence of the U 5 electrons and the Ru substitution. From the sum rule analysis for the XMCD spectra, it was found that the magnetic moments of the U 5 and Co 3 electrons in UCoGe and U(CoRu)Ge are aligned in the same direction under the present experimental conditions; 
= 5.5 - 50 K and 
= 0 - 10 T. Furthermore, even in the case of YCoGe, the Co 3 electrons have a large orbital magnetic moment, suggesting that the Co 3 electrons in these compounds are in a low symmetric electronic environment originally. Through the - and -dependence of the XMCD intensity, it was revealed that the magnetic properties at the Co site are not simply induced by the magnetism at the U site and that the Co 3 electrons play an important role in the stability of ferromagnetism.
cuprates岩澤 英明*; 角田 一樹; 石田 茂之*; Le F
vre, P.*; Bertran, F.*; 吉田 良行*; 永崎 洋*; Santander-Syro, A.*; 奥田 太一*
Scientific Reports (Internet), 13, p.13451_1 - 13451_7, 2023/08
The role of spin-orbit interaction has been recently reconsidered in high- cuprates, stimulated by the recent experimental observations of spin-polarized electronic states. However, due to the complexity of the spin texture reported, the origin of the spin polarization in high- cuprates remains unclear. Here, we present the spin- and angle-resolved photoemission spectroscopy (ARPES) data on the facing momentum points that are symmetric with respect to the 
point, to ensure the intrinsic spin nature related to the initial state. We consistently found the very weak spin polarization only along the nodal direction, with no indication of spin-splitting of the band. Our findings thus call for a revision of the simple application of the spin-orbit interaction, which has been treated within the standard framework of the Rashba interaction in high- cuprates.
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
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。
neutron diffraction study on the deformation behavior of the plastic inorganic semiconductor AgSWang, Y.*; Gong, W.; 川崎 卓郎; Harjo, S.; Zhang, K.*; Zhang, Z. D.*; Li, B.*
Applied Physics Letters, 123(1), p.011903_1 - 011903_6, 2023/07
被引用回数：0Bulk AgS is a plastic inorganic semiconductor at room temperature. It exhibits a compressive strain greater than 50%, which is highly different from brittle conventional counterparts, such as silicon. Here, we present the experimental investigation of the deformation behavior in a plastic inorganic semiconductor AgS using 
neutron diffraction during compressive deformation at room and elevated temperatures. At room temperature, the lattice strain partitioning among 
-orientated grain families could be responsible for the significant work-hardening behavior in the bulk AgS with a monoclinic structure. The rapid accumulation of lattice defects and remarkable development of the deformation texture suggest that dislocation slip promotes plasticity. At 453 K, a monoclinic phase transforms into a body-centered cubic phase. A stress plateau appears at 
-4.8 MPa, followed by a rehardening state. The deformation mode of bulk AgS at the initial stage is likely attributable to the migration of silver ions, and as strain increases, it is closer to that of room temperature, leading to rehardening.
斉藤 拓巳*; 元川 竜平; 大窪 貴洋*; 三浦 大輔*; 熊田 高之
Environmental Science & Technology, 57(26), p.9802 - 9810, 2023/07
被引用回数：0 パーセンタイル：0.01(Engineering, Environmental)Aggregation of humic acids (HAs) were studied by small-angle neutron and X-ray scattering techniques. The combination of these techniques enables us to examine aggregation structures of heterogeneous HA particles. Two HAs with distinctive compositions were examined; a commercial HA (PAHA) and a HA extracted from deep sedimentary groundwater (HHA). While macroscopic coagulation tests showed that these HAs were stable in solutions except for HHA at pH 
6, small-angle neutron scattering (SANS) and X-ray scattering (SAXS) revealed that they formed aggregates with the sizes exceeding sub-micrometer length scale. The SAXS curves of PAHA remarkably varied with pD, whereas the SANS curves did not. With the help of theoretical fittings, it was revealed that PAHA aggregates consisted of two domains: poorly hydrated cores and well-hydrated proton-rich shells. The cores are (dis)aggregated with pD inside the aggregates of the shell. The SANS and SAXS curves of HHA resemble each other, and their intensities at low q increased with a decrease of pD, indicating the formation of homogeneous aggregates. This study revealed that distinctive aggregation behaviors exist in humic substances with heterogeneous structures like PAHA, which is invaluable for their roles in the fate of contaminants or nutrients in aqueous environments.
Bersweiler, M.*; 佐藤 宏和*; 足立 望*; 戸高 義一*; Peral, I.*; Kohlbrecher, J.*; Zaporozhets, V. D.*; Metlov, K. L.*; Michels, A.*; 大場 洋次郎
IUCrJ, 10(4), p.411 - 419, 2023/07
被引用回数：1Magnetic microstructures in severely deformed iron produced via high-pressure torsion (HPT) straining have been investigated using small-angle neutron scattering. The results reveal that nonneglibible third-order scattering contribution in the inhomogeneities amplitude of magnetization is induced via HPT straining and the contribution becomes small with subsequent annealing. The contribution has negative values, which suggest that the inhomogeneity of the magnetic anisotropy enhanced via HPT is a possible origin of the third-order contribution.
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：0 パーセンタイル：0.01(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 CoTaS
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.
X-ray synchrotron diffractionLi, H.*; Liu, Y.*; Zhao, W.*; Liu, B.*; 冨永 亜希; 菖蒲 敬久; Wei, D.*
International Journal of Plasticity, 165, p.103612_1 - 103612_20, 2023/06
被引用回数：0 パーセンタイル：0.01(Engineering, Mechanical)コバルトフリーのマルエージング鋼の強度特性を明らかにするために、高エネルギー放射光X線回折法を利用したその場引張試験を行った。マルテンサイト相とオーステナイト相からの回折プロファイルが得られ、それらの強度及び幅が負荷に伴い変化している様子が観察された。回折プロファイルを解析した結果、時効(as-aged)材では、低応力レベルにてマルテンサイトの含有量が緩やかに減少し、高応力レベルでは急激に減少した。一方、熱処理(as-solution)材では、応力の増加とともにオーステナイト相がマルテンサイト相に著しく転移変態している結果が得られた。これらのことがそれぞれの強度特性に起因していることを明らかにした。
AuGe ( = Y, Gd-Tm, and Lu)車地 崇*; 厳 正輝*; 鬼頭 俊介*; 池内 和彦*; 中村 充孝; 池田 暁彦*; 有馬 孝尚*
Journal of Alloys and Compounds, 947, p.169475_1 - 169475_8, 2023/06
被引用回数：0 パーセンタイル：0.01(Chemistry, Physical)We study structural and magnetic properties of rare-earth based semimetals 
AuGe ( = Y, Gd-Tm, and Lu) using flux-grown single crystals. We evaluate the crystal electric field parameters based on the Stevens operators to reasonably reproduce the temperature dependence of magnetic susceptibilities and specific heat for RAuGe ( = TbTm). The estimated energy scale of the Ising gap ( 11 meV) in TmAuGe is consistent with an excitation observed in an inelastic neutron scattering experiment. These findings suggest an opportunity for interplay between conduction electrons and nontrivial spin structures in the family of magnetic polar semimetals AuGe.
