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論文

Facile preparation of antiviral grafted fabrics based on silver-immobilized phosphate groups and evaluation of COVID-19 infections

松村 大樹; 辻 卓也; 瀬古 典明*; 他5名*

Journal of Radioanalytical and Nuclear Chemistry, 335(2), p.1543 - 1552, 2026/02

https://doi.org/10.1007/s10967-025-10608-y
 被引用回数：0 パーセンタイル：0.00(Chemistry, Analytical)

The COVID-19 pandemic has underscored the need for protective materials with rapid and durable antiviral properties. We developed silver (Ag)-immobilized fabrics via radiation-induced graft polymerization and tested their activity against SARS-CoV-2. The fabrics reduced 40,000 viral particles to below detection within one hour, showed no Ag leaching after 24 h in water, and retained complete antiviral performance after one year of storage. These findings demonstrate the long-term stability and strong potential of Ag-immobilized fabrics for industrial use in protective equipment.

論文

Nanointerface coupling activates earth-abundant elements for enhanced oxygen evolution electrode process

Wang, M.*; 坂牛 健*; 辻 卓也; 松村 大樹; 他9名*

Journal of Physical Chemistry C, 130(2), p.931 - 941, 2026/01

https://doi.org/10.1021/acs.jpcc.5c06544
 被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)

Understanding how compositional complexity influences electrocatalytic kinetics remains a major challenge in the design of multicomponent materials. The multifaceted interactions between constituent elements are able to obscure the factors governing kinetics of electrode processes. Here, we introduce a small compositional change to modulate the rate-determining step of the oxygen evolution reaction (OER) by tuning the binding energies of key intermediates. We combine advanced characterization, including ${it in situ}$ electrochemical X-ray absorption spectroscopy, with first-principles calculations to demonstrate that the drastic enhancement in OER activity of MnFeNi-based materials is driven by synergistic interactions among the constituent elements. This enhancement stems from targeted modulation of intrinsic reaction pathways, shifting the rate-determining step via controlled stabilization of key intermediates. Our findings introduce a clear viewpoint for understanding how compositional tuning governs kinetics in complex electrocatalytic systems, offering new design principles for next-generation electrochemical materials.

論文

Redox dynamics of cerium ions in soda-lime glass during cooling analyzed by in situ X-ray absorption fine structure

小澤 沙記*; 塩沢 優大*; 西條 佳孝*; 宮嶋 達也*; 松村 大樹; 辻 卓也; 中瀬 正彦*; 前原 輝敬*

Journal of the American Ceramic Society, 109(3), 10 Pages, 2026/00

https://doi.org/10.1111/jace.70621
 被引用回数：0

The optical properties of glass are strongly influenced by the redox states of trace multivalent elements. Ce$$^{4+}$$ ions are commonly added to soda-lime glass to remove Fe$$^{2+}$$-induced coloration via the redox reaction Ce$$^{4+}$$ + Fe$$^{2+}$$ $$rightarrow$$ Ce$$^{3+}$$ + Fe$$^{3+}$$ during cooling. Herein, the redox dynamics of cerium ions in soda-lime glass melts during model industrial cooling processes (from 1523 K at 20 K$$cdot$$min$$^{-1}$$) were investigated using in situ time-resolved Ce K-edge dispersive X-ray absorption fine-structure (DXAFS) spectroscopy. To evaluate the effect of the iron concentration, three soda-lime glass samples containing 2 mass% CeO$$_{2}$$ were examined: Fe-free, Fe-05 (0.5 mass% Fe$$_{2}$$O$$_{3}$$), and Fe-20 (2.0 mass% Fe$$_{2}$$O$$_{3}$$). Above 1383 K, the Ce$$^{3+}$$/total Ce ratio remained stable for all samples, showing no significant change during cooling. Below 1383 K, the ratio decreased for the Fe-free glass, indicating the oxidation of Ce$$^{3+}$$ ions, and increased for the Fe-containing glass owing to the reduction of Ce$$^{4+}$$ ions. The temperature dependence of the redox change (${it $Delta$}$Ce redox) showed Fe-dependent behavior: Fe-20 exhibited more pronounced Ce$$^{4+}$$ reduction above 1200 K, while Fe-05 showed accelerated changes mainly below approximately 1100 K. These results indicate that cerium oxidation in Fe-free glass is strongly influenced by oxygen transport limitations, while cerium reduction is closely associated with availability of Fe$$^{2+}$$ ions, providing quantitative insights into the control of Ce-based decolorization during industrial cooling.

論文

Change in dislocation density via ausforming in Fe-5%Mn-C alloy with lath martensitic structure

高梨 美咲*; 日高 僚太*; 大久保 亘太*; 増村 拓朗*; 土山 聡宏*; 諸岡 聡; 前田 拓也*; 中村 修一*; 植森 龍治*

ISIJ International, 65(9), p.1384 - 1393, 2025/08

https://doi.org/10.2355/isijinternational.ISIJINT-2025-090
 被引用回数：0

This study investigates the strengthening mechanism of ausforming in martensitic steels, focusing on the role of dislocation inheritance from austenite. By analyzing Fe-5%Mn-C alloys, the researchers quantified dislocation densities before and after ausforming and examined how carbon content affects hardening. Results show that both hardness and dislocation density of ausformed martensite increase with greater deformation in austenite and higher carbon content. The findings support that ausforming strengthens martensite through dislocation accumulation, consistent with the Bailey-Hirsch relationship. ${it In-situ}$ neutron diffraction revealed that dislocation inheritance occurs only in steels with sufficient carbon, while additional dislocations are introduced during martensitic transformation.

論文

Absence of long-range V-V dimer and magnetic orderings in high-entropy (Mg$$_{0.2}$$Mn$$_{0.2}$$Co$$_{0.2}$$Ni$$_{0.2}$$Cu$$_{0.2}$$)VO$$_3$$

山本 孟*; 辻 卓也; 松村 大樹; 他16名*

Inorganic Chemistry, 64(34), p.17496 - 17502, 2025/08

https://doi.org/10.1021/acs.inorgchem.5c02779
 被引用回数：0 パーセンタイル：0.00(Chemistry, Inorganic & Nuclear)

V-V dimerization in ilmenite-type vanadium oxides is an intriguing phenomenon that induces structural and metal-to-insulator transitions. Herein, we report the high-pressure synthesis, crystal structure, and electronic states of high-entropy ilmenite-type (Mg$$_{0.2}$$Mn$$_{0.2}$$Co$$_{0.2}$$Ni$$_{0.2}$$Cu$$_{0.2}$$)VO$$_3$$. Although all the parent ilmenite-type compounds exhibit triclinic ($$P$$$$bar{1}$$) symmetry, this compound crystallizes in a rhombohedral ($$R$$$$bar{3}$$) structure, indicating the absence of V-V dimer ordering. The temperature dependence of the resistivity below room temperature follows a variable-range hopping conduction mechanism, suggesting the presence of short-range V-V dimer ordering. Magnetic susceptibility and heat capacity measurements revealed multi-step spin-glass transitions. This study demonstrates that a high-entropy composition hinders electronic and magnetic long-range ordering due to severe lattice distortions and competition between magnetic exchange interactions.

論文

Cu/ZnO catalysts integrated with Al$$_{2}$$O$$_{3}$$ and/or SiO$$_{2}$$ for methanol synthesis; Deciphering the additive-induced boost in catalytic performance by XAFS

Iwasaki, Kosei*; Ashida, Yuya*; 松村 大樹; Kawakami, Kotaro*; Shibuya, Kana*; Tazawa, Masaru*; 辻 卓也; Shimizu, Hajime*

Journal of CO$$_{2}$$ Utilization, 97, p.103111_1 - 103111_9, 2025/07

https://doi.org/10.1016/j.jcou.2025.103111
 被引用回数：2 パーセンタイル：64.02(Chemistry, Multidisciplinary)

The development of active, long-lived methanol synthesis catalysts can be expedited by thoroughly understanding the operating mechanisms of promoter additives. SiO$$_{2}$$ serves as an effective support and promoter for Cu/ZnO-type methanol synthesis catalysts; however, it has not been studied as extensively as the industrially predominant Al$$_{2}$$O$$_{3}$$, despite being similarly potent. Therefore, we conducted X-ray absorption fine structure predominant Al$$_{2}$$O$$_{3}$$, despite being similarly potent. Therefore, we conducted X-ray absorption fine structure studies to probe the effects of incorporating Al$$_{2}$$O$$_{3}$$ and SiO$$_{2}$$ additives into Cu/ZnO-based heterogeneous catalysts. The results revealed that the additive elements primarily affected the ability of the Zn species to generate oxygen vacancies by distorting the local structure around element-doped ZnO and that the number of oxygen vacancies correlated to the catalytic activity. Additionally, the oxygen vacancies in ZnO in the Al/Si-incorporated catalysts diminished under catalytic reaction conditions, thereby providing information on the deactivation of catalytic reactions. Our findings can facilitate the development of highly active industrial-grade methanol synthesis catalysts.

論文

Change in dislocation density via ausforming in Fe-5%Mn-C alloy with lath martensitic structure

高梨 美咲*; 日高 僚太*; 大久保 亘太*; 増村 拓朗*; 土山 聡宏*; 諸岡 聡; 前田 拓也*; 中村 修一*; 植森 龍治*

鉄と鋼, 111(9), p.503 - 513, 2025/06

https://doi.org/10.2355/tetsutohagane.TETSU-2024-092
 被引用回数：0 パーセンタイル：0.00(Metallurgy & Metallurgical Engineering)

The strengthening mechanism of ausforming in martensitic steels is believed to be due to the inheritance of dislocations in austenite by the subsequently transformed martensite. However, no studies to date have quantified the dislocation density before and after ausforming. In this study, the dislocation densities of Fe-5%Mn-C alloys were analyzed, and the relationship between hardening by ausforming and dislocation accumulation, as well as the effect of carbon on this relationship, were investigated. The hardness of ausformed martensite increased with the ausforming reduction in austenite, and the strengthening effect of ausforming increased with the addition of carbon. Similarly, the dislocation density of ausformed martensite increased with the ausforming reduction in austenite, and the dislocation accumulation by ausforming increased with the addition of carbon. Because the hardness of the ausformed martensite follows the Bailey-Hirsch relationship, the strengthening mechanism owing to ausforming could be explained by dislocation strengthening. To understand the dislocation accumulation process during ausforming, the dislocation density of austenite immediately after ausforming was measured by in-situ heating neutron diffraction. Consequently, the dislocation density of the ausformed austenite was not dependent on the carbon content, indicating that dislocations are not inherited in carbon-free steels. By contrast, in steels with sufficient carbon content, not only are dislocations inherited but additional dislocations are introduced during martensitic transformation.

論文

Spontaneous magnetic field and disorder effects in BaPtAs$$_{1-x}$$Sb$$_x$$ with a honeycomb network

足立 匡*; Ogawa, Taiki*; 小宮山 陽太*; 須村 拓也*; Saito-Tsuboi, Yuki*; Takeuchi, Takaaki*; Mano, Kohei*; Manabe, Kaoru*; 川端 幸樹*; 今津 毅士*; et al.

Physical Review B, 111(10), p.L100508_1 - L100508_6, 2025/03

https://doi.org/10.1103/PhysRevB.111.L100508
 被引用回数：1 パーセンタイル：0.00(Materials Science, Multidisciplinary)

Chiral superconductivity exhibits the formation of novel electron pairs that breaks the time-reversal symmetry and has been actively studied in various quantum materials in recent years. However, despite its potential to provide definitive information, effects of disorder in the crystal structure on the chiral superconductivity has not yet been clarified, and therefore the investigation using a solid-solution system is desirable. We report muon-spin-relaxation ($$mu$$SR) results of layered pnictide BaPtAs$$_{1-x}$$Sb$$_x$$ with a honeycomb network composed of Pt and (As, Sb). We observed an increase of the zero-field $$mu$$SR rate in the superconducting (SC) state at the Sb end of $$x=1.0$$, suggesting the occurrence of a spontaneous magnetic field due to the time-reversal symmetry breaking in the SC state. On the other hand, a spontaneous magnetic field was almost and completely suppressed for the As-Sb mixed samples of $$x=0.9$$ and 0.2, respectively, suggesting that the time-reversal symmetry-breaking SC state in $$x=1.0$$ is sensitive to disorder. The magnetic penetration depth estimated from transverse-field $$mu$$SR measurements at $$x=1.0$$ and 0.2 behaved like weak-coupling $$s$$-wave superconductivity. These seemingly incompatible zero-field and transverse-field $$mu$$SR results of BaPtAs$$_{1-x}$$Sb$$_x$$ with $$x=1.0$$ could be understood in terms of chiral $$d$$-wave superconductivity with point nodes on the three-dimensional Fermi surface.

論文

Valence separation of Fe and removal of Sn$$^{2+}$$ by solvent extraction as a potential method to determine Fe$$^{2+}$$ in glass containing Sn$$^{2+}$$

菅野 直樹*; 中瀬 正彦*; 西條 佳孝*; 松村 大樹; 辻 卓也; 竹下 健二*; 塚原 剛彦*

Progress in Nuclear Science and Technology (Internet), 7, p.154 - 160, 2025/03

https://doi.org/10.15669/pnst.7.154

The amounts of Fe$$^{2+}$$ and Fe$$^{3+}$$ present in glass are important indicators of its optical properties because even small amounts have significant effects. However, it is challenging to use wet chemical analysis to determine the concentration and the ratio of Fe$$^{2+}$$ and Fe$$^{3+}$$ in glass when it contains Sn because of the redox reaction between Sn$$^{2+}$$ and Fe$$^{3+}$$ in the glass decomposition solution. A two-step approach was tested to determine the concentrations of Fe$$^{2+}$$ and Fe$$^{3+}$$ in a glass decomposition solution in the presence of Sn$$^{2+}$$. In the first step, the redox reaction between Sn$$^{2+}$$ and Fe$$^{3+}$$ was suppressed by increased pH. In the second step, Sn$$^{2+}$$ was removed from the glass decomposition solution by solvent extraction. To understand the kinetics of the redox reaction between Sn$$^{2+}$$ and Fe$$^{3+}$$, time-resolved dispersive X-ray absorption fine structure and ultraviolet-visible absorption spectroscopy (UV-vis) were used with standard chloride solutions of Sn and Fe in respective valences. We found that lowering the acid concentration suppressed redox reactions. The partitioning behaviors of Sn$$^{2+}$$, Sn$$^{4+}$$, Fe$$^{2+}$$, and Fe$$^{3+}$$ by bis(2-ethylhexyl) hydrogen phosphate (D2EHPA) as an extractant in ${it n}$-dodecane were investigated to see the removal ability of Sn$$^{2+}$$ from the glass decomposition solution. As a result, D2EHPA in ${it n}$-dodecane could extract Sn$$^{2+}$$, Sn$$^{4+}$$, and Fe$$^{3+}$$ into the organic phase, and Fe$$^{2+}$$ remained in the aqueous phase. The simultaneous removal of Sn$$^{2+}$$ and Sn$$^{4+}$$ and the separation of Fe$$^{2+}$$ and Fe$$^{3+}$$ became possible. This method can potentially apply to the rapid analysis of the concentration of Fe$$^{2+}$$ and Fe$$^{3+}$$ in a glass containing tin oxide.

論文

乾燥-湿潤過程における粘土鉱物のCs収着構造の解明

辻 卓也; 松村 大樹; 小林 徹

SPring-8/SACLA利用研究成果集(インターネット), 12(5), p.259 - 262, 2024/10

https://doi.org/10.18957/rr.12.5.259

2:1型層状粘土鉱物には層を構成する陽イオンが同形置換することで層電荷を持ち、層間に陽イオンを取り込むことで電荷を補償する。また、層電荷の大小により異なる膨潤性を示す。風化黒雲母は比較的大きい層電荷をもつため膨潤性が低く、モンモリロナイトは層電荷が小さいため膨潤性が高い。アルミノケイ酸塩であるゼオライトは様々な細孔を持ち、その内部に水分子を持つ。これらの粘土鉱物中では、降雨等の環境の変化により異なるセシウム収着構造をとることが考えられるため、本研究では湿潤・乾燥・再湿潤状態の粘土鉱物試料に対し、Cs K吸収端X線吸収分光(X-ray Absorption Fine Structure, XAFS)測定によりセシウム近傍の局所構造解析を行った。その結果、湿潤・乾燥試料においては水分子の存在により、一部の収着サイトではセシウムを収着しにくくなり、乾燥・再湿潤試料においては収着構造に差はなく、不可逆的にセシウムが収着していることが示唆された。

論文

Nearly linear orbital molecules on a pyrochlore lattice

Krajewska, A.*; 辻 卓也; 松村 大樹; 他15名*

Science Advances (Internet), 10(41), p.eadn3880_1 - eadn3880_10, 2024/10

https://doi.org/10.1126/sciadv.adn3880
 被引用回数：4 パーセンタイル：62.32(Multidisciplinary Sciences)

The interplay of spin-orbit coupling with other relevant parameters gives rise to the rich phase competition in complex ruthenates featuring octahedrally coordinated Ru$$^{4+}$$. While locally, spin-orbit coupling stabilizes a non-magnetic $$J_{rm eff}$$ = 0 state, intersite interactions resolve one of two distinct phases at low temperatures: an excitonicmagnet stabilized by the magnetic exchange of upper-lying $$J_{rm eff}$$ = 1 states or Ru$$_{2}$$ molecular orbital dimers driven by direct orbital overlap. Pyrochlore ruthenates A$$_{2}$$Ru$$_{2}$$O$$_{7}$$ (A = rare earth, Y) are candidate excitonic magnets with geometrical frustration. We synthesized In$$_{2}$$Ru$$_{2}$$O$$_{7}$$ with covalent In-O bonds. This pyrochlore ruthenate hosts alocal $$J_{rm eff}$$ = 0 state at high temperatures; however, at low temperatures, it forms a unique nonmagnetic ground state with nearly linear Ru-O-Ru molecules, in stark contrast to other A$$_{2}$$Ru$$_{2}$$O$$_{7}$$ compounds. The disproportionation of covalent In-O bonds drives Ru$$_{2}$$O molecule formation, quenching not only the local spin-orbit singlet but also geometrical frustration.

論文

Local and electronic structures of NaNbO$$_3$$, AgNbO$$_3$$, and KNbO$$_3$$

米田 安宏; 小林 徹; 辻 卓也; 松村 大樹; 斎藤 祐児; 野口 祐二*

Japanese Journal of Applied Physics, 63(9), p.09SP12_1 - 09SP12_10, 2024/09

https://doi.org/10.35848/1347-4065/ad72fc
 被引用回数：3 パーセンタイル：40.38(Physics, Applied)

NaNbO$$_3$$、AgNbO$$_3$$、KNbO$$_3$$のABO$$_3$$型ペロブスカイト系は良好な強誘電特性を持つことが知られている。我々は局所構造解析により各原子のラットリング空間を直接決定した。この解析により、大きな揺らぎを持つ結合サイトがイオンサイズの変化によって変化することを明らかにした。軟X線吸収分光法を含む実験から、Aサイトイオンは酸素と混成していることがわかった。

論文

Continuous structural phase transition and antiferromagnetic order in ilmenite-type NiVO$$_{3}$$

山本 孟*; 池田 理*; 本田 孝志*; 木村 健太*; 青山 拓也*; 大串 研也*; 鈴木 昭夫*; 石井 賢司*; 松村 大樹; 辻 卓也; et al.

Physical Review Materials (Internet), 8(9), p.094402_1 - 094402_6, 2024/09

https://doi.org/10.1103/PhysRevMaterials.8.094402
 被引用回数：4 パーセンタイル：32.24(Materials Science, Multidisciplinary)

We investigate the crystal and electronic structures as well as magnetic properties of ilmenite-type NiVO$$_{3}$$, which has attracted research interest as an ${it S}$ = 1 honeycomb lattice magnet. Ilmenite-type NiVO$$_{3}$$ samples were synthesized under high-pressure and high-temperature conditions. Synchrotron X-ray diffraction and Rietveld refinement results demonstrated that NiVO$$_{3}$$ underwent a continuous structural phase transition from the triclinic (${it P$bar{1}$}$) phase to the rhombohedral (${it R$bar{3}$}$) phase at 450 K. This transition is concomitant with the decomposition of the V-V dimers formed by the tetravalent V ions. X-ray absorption spectroscopy measurements confirmed that the Ni and V ions were divalent and tetravalent, respectively. Magnetic and specific heat measurements revealed that NiVO$$_{3}$$ underwent an antiferromagnetic transition at 140 K, and a zigzag-type magnetic order with magnetic propagation vector ${it k}$=(0,1/2,0) was observed by neutron diffraction measurements.

論文

Effects of Fe ions, ultraviolet irradiation, and heating on microscopic structures of black lacquer films

南川 卓也; 関根 由莉奈; 松村 大樹; 廣井 孝介; 高田 慎一; 神谷 嘉美*; 本多 貴之*

Langmuir, 40(11), p.5725 - 5730, 2024/03

https://doi.org/10.1021/acs.langmuir.3c03412
 被引用回数：2 パーセンタイル：23.38(Chemistry, Multidisciplinary)

鉄と漆の化学反応を利用して、古くから黒漆が作られている。しかし、鉄と漆の反応については、ほとんど知られていない。本研究では、黒漆中のFeイオンの化学状態を、XANES, EXAFS、SAXS, SANSおよびFT-IRを使用して調査した。Fe(II)またはFe(III)を生漆に添加し、空気乾燥,加熱、またはUV照射により黒漆フィルムを作成した。これらのサンプルのXANESスペクトルの測定結果から、最初に添加したFeの酸化状態に関係なく、サンプル内のFeイオンが3価の状態で存在していることが明らかとなった。また、すべてのフィルムサンプルのEXAFSスペクトルは同様の形状であったが、ピーク強度は、空気乾燥$$>$$UV照射$$>$$加熱の順に減少した。この結果は、加熱やUV照射により黒漆中のFeの配位構造が不均一になり、加熱が最も不均一になったことを示している。サンプルのFT-IRスペクトルの変化は、ウルシオールの重合挙動が空気乾燥,加熱、およびUV照射下でも異なり、漆中での反応により、Feの配位構造が不均一になることが明らかとなった。このような結果から、XANESやEXAFSスペクトルは、黒漆の情報を簡易に得る手法として有用であり、貴重な文化財の黒漆の非破壊分析に特に有効である。

論文

Local structure analysis of Bi$$_{0.5}$$Na$$_{0.5}$$TiO$$_3-$$BaTiO$$_3$$ solid solutions

米田 安宏; 小林 徹; 辻 卓也; 松村 大樹; 斎藤 祐児; 野口 祐二*

Japanese Journal of Applied Physics, 62(SM), p.SM1006_1 - SM1006_8, 2023/11

https://doi.org/10.35848/1347-4065/ace3cd
 被引用回数：6 パーセンタイル：48.05(Physics, Applied)

Bi$$_{0.5}$$Na$$_{0.5}$$TiO$$_3-$$BaTiO$$_3$$ (BNT$$-$$BT)固溶体は良い圧電特性を示すため多くの研究が行われてきた。また、BT組成に応じてバラエティーに富んだ相が観測される。BNT$$-$$BT固溶体の軟X線吸収分光実験と高エネルギーX線回折実験を放射光を利用して行った。得られたBNT$$-$$BT固溶体の電子構造と局所構造から、BTの置換効果は主にBaの置換サイトであるAサイトで起こっていることがわかった。BT組成の変化に対してTiO$$_6$$八面体の菱面体晶ひずみは変化しておらず、O-K吸収端で生じた電子構造の変化は混成状態の変化であると考えられる。

論文

分散型光学系を用いた時間分解X線吸収分光法によるRh金属微粒子触媒のCO酸化反応における自発振動現象の詳細観測

松村 大樹; 木村 優作*; 辻 卓也; 水木 純一郎*

SPring-8/SACLA利用研究成果集(インターネット), 11(5), p.296 - 299, 2023/11

https://doi.org/10.18957/rr.11.5.296

自発振動現象を起こすRh金属微粒子触媒上のCO酸化反応について、分散型光学系による時間分解X線吸収分光法を用いた研究を実施した。定常ガスを一定温度で導入して、触媒反応の振動現象が起こっている最中のRh金属微粒子の構造変化について、1Hz程度のフレームレートで詳細観測した。触媒反応生成物であるCO$$_{2}$$濃度の時間変化とX線吸収分光法によるRh金属微粒子構造の時間変化とを比べると、両者は強く相関していることが見て取れた。振動構造の様式には、Rhの平均価数変化は階段状のものである一方CO$$_{2}$$の生成量はパルス状の変化であるという違いがあり、これは金属Rh表面で短時間のみ吸着COが無い状態が実現されるという考えで解釈できた。

論文

Local atomic displacements and sign of the structural transformation in medium-entropy alloys observed in extended X-ray absorption fine structure spectra

池田 陽一*; 梅本 好日古*; 松村 大樹; 辻 卓也; 橋本 勇輝*; 北澤 崇文*; 藤田 全基*

Materials Transactions, 64(9), p.2254 - 2260, 2023/09

https://doi.org/10.2320/matertrans.MT-M2023043
 被引用回数：4 パーセンタイル：30.19(Materials Science, Multidisciplinary)

Extended X-ray absorption fine structure (EXAFS) and neutron diffraction experiments were carried out to clarify the typical features of the local structure of a family of medium-entropy alloys (CrCoNi, MnCoNi, and FeCoNi). A simple random cluster model was constructed for analyzing EXAFS spectra, and static and dynamic components of the mean-square relative displacement (MSRD) were separately extracted. In our analysis, the static MSRD of the MnCoNi sample was slightly larger than those of the CrCoNi and FeCoNi samples, whereas the dynamic MSRDs of these samples were almost identical. Based on the complementary neutron diffraction data, we argued that the origin of the large static displacement in the MnCoNi alloy can be associated with a short-range structural transformation through long-term structural relaxation.

論文

Local structure analysis of DyN-ZrN solid solutions

米田 安宏; 辻 卓也; 松村 大樹; 岡本 芳浩; 高木 聖也; 高野 公秀

Physica B; Condensed Matter, 663, p.414960_1 - 414960_9, 2023/08

https://doi.org/10.1016/j.physb.2023.414960
 被引用回数：0 パーセンタイル：0.00(Physics, Condensed Matter)

DyN-ZrN固溶体の局所構造と平均構造を抽出するために、放射光X線を用いた種々の測定を行った。X線吸収微細構造(XAFS)と高エネルギーX線回折を組み合わせてナノスケールの構造解析を行い、DyN-ZrN固溶体の構造不安定性を議論した。DyN-ZrN固溶体は岩塩型立方晶の結晶構造を持ち、金属サイトの化学秩序や窒素サイトの結合長分布などの不安定性があり、相分離や構造不連続の原因となっていることがわかった。

論文

Cs ${it L$_{1}$}$吸収端XAFS測定による各種粘土鉱物中におけるセシウムの収着構造

辻 卓也; 松村 大樹; 小林 徹

SPring-8/SACLA利用研究成果集(インターネット), 11(4), p.214 - 217, 2023/08

https://doi.org/10.18957/rr.11.4.214

天然に存在する粘土鉱物は様々な層構造をもち、セシウムイオン等の陽イオン収着サイトは複数存在すると考えられており、層間サイト、表面サイトや端面サイト等が存在すると考えられている。福島第一原子力発電所事故後に放射性セシウムにより汚染された土壌中での詳細な収着構造解明のため、本研究ではセシウムを飽和収着させた粘土鉱物試料に対しCs ${it L$_{1}$}$吸収端X線吸収分光(X-ray absorption fine structure, XAFS)測定を行い、セシウム収着様式の比較を行った。その結果、各種粘土鉱物においてスペクトルの詳細構造に差がみられ、四面体シートや八面体シートへの収着等、収着構造の違いに起因するセシウム収着様式の違いが明らかになった。

論文

Cu $$K$$-edge X-ray absorption fine structure study of $$T'$$-type $$RE$$$$_{2}$$CuO$$_{4+alpha-delta}$$ ($$RE$$ = Rare Earth); Toward unified understanding of electronic state of $$T'$$-type cuprate

Chen, Y.*; 浅野 駿*; Wang, T.*; Xie, P.*; 北山 慎之介*; 石井 賢司*; 松村 大樹; 辻 卓也; 谷口 貴紀*; 藤田 全基*

JPS Conference Proceedings (Internet), 38, p.011050_1 - 011050_6, 2023/05

https://doi.org/10.7566/JPSCP.38.011050

To investigate the variation of the electronic state of $$T'$$-type cuprate due to annealing, we performed Cu $$K$$-edge X-ray absorption fine structure measurements on Pr$$_{2}$$CuO$$_{4+alpha-delta}$$ (PCO) and Pr$$_{1.3}$$La$$_{0.7}$$CuO$$_{4+alpha-delta}$$ (PLCO). The induced electrons due to annealing ($$n_{AN}$$) in PCO and PLCO were approximately 2$$delta$$, consistent with a model of electron doping to Mott insulator. Here, $$alpha$$ and $$delta$$ represent the amount of excess oxygen from the stoichiometric composition in the as-sintered compound and that of oxygen loss due to annealing, respectively. Furthermore, the energy of the Einstein oscillator ($$hbaromega_{E}$$) for the Cu-O$$_{p}$$ bond was evaluated by extended X-ray absorption fine structure analysis. (O$$_{p}$$ denotes the in-plane oxygen.) We found a small annealing effect on $$hbaromega_{E}$$ for both PCO and PLCO.

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