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As studied by X-ray magnetic circular dichroismWan, Y.*; 芝田 悟朗; 竹田 幸治*; 岡根 哲夫; 斎藤 祐児; 山上 浩志; 藤森 淳*; 他10名*
Physical Review Materials (Internet), 10(5), p.054402_1 - 054402_8, 2026/05
In order to unveil the nature of the ferromagnetism in (Ba,K)(Zn,Mn)As, its magnetization process has been studied by X-ray magnetic circular dichroism (XMCD) at the Mn 
edge in a wide range of temperature and magnetic field. The average magnetization of the Mn atoms as a function of magnetic field (
-
curves) at various temperatures could be successfully explained by a mixture of paramagnetic (PM), superparamagnetic (SPM), and ferromagnetic (FM) components as previously reported for GaMnAs, revealing the complex nature of the ferromagnetism in (Ba,K)(Zn,Mn)As. The average magnetization of the SPM clusters of different sizes and the FM regions were found to be small compared to those in GaMnAs, which we attribute to the antiferromagnetic interaction between nearest-neighbor Mn atoms in (Ba,K)(Zn,Mn)As on the basis of recent theoretical predictions.
CaOsO
assessed by X-ray magnetic dichroism measurements芝田 悟朗; 藤森 淳*; 他10名*
Physical Review B, 113(16), p.165151_1 - 165151_7, 2026/04
We studied the cubic double perovskite Ba
CaOsO
containing the Os
(
) ions, which exhibits a phase transition to a `hidden order' below 
K, by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the Os edge. The cubic ligand-field splitting between the 
and 
levels of Os 
was deduced by XAS to be 
eV. The temperature dependence of the XMCD spectra was consistent with a 
meV residual cubic splitting of the lowest 
multiplet state into the non-Kramers 
doublet ground state and the 
triplet excited state. Ligand-field (LF) multiplet calculation under fictitious strong magnetic fields indicated that the exchange interaction between nearest-neighbor octupoles should be as strong as 
meV if a ferro-octupole order is stabilized in the `hidden-ordered' state, consistent with the exchange interaction of 
meV previously predicted theoretically using model and density functional theory calculations.
寺澤 知潮; 勝部 大樹*; 矢野 雅大; 小澤 孝拓*; 津田 泰孝; 吉越 章隆; 朝岡 秀人; 鈴木 誠也
Chemistry of Materials, 38(6), p.2933 - 2945, 2026/03
被引用回数：0 パーセンタイル：0.00Germanene, a honeycomb lattice of Ge atoms, has attracted attention for next-generation electronics and as a topological material. Among reported synthesis routes, the segregation method enables reproducible monolayer germanene formation on Ag(111) through simply annealing an Ag(111) thin film on a Ge(111) substrate. Despite this success, the physical origins of its monolayer selectivity and the mechanism for suppressing competing Ge phases remain unclear. Here, we investigate germanene formation via Ge segregation using in situ Raman spectroscopy and X-ray photoelectron spectroscopy to directly track Ge behavior during annealing and cooling. In situ observations revealed that annealing at 500
C yielded no Ge-related byproducts, and the system reached a high-temperature surface equilibrium state, independent of the initial Ge amount. Cooling from this state produced a Ge-enriched surface that stabilizes the formation of monolayer germanene. In contrast, heating only to 300C produced three-dimensional Ge islands without Ge-enrichment, followed by Ge-Ag alloy formation upon subsequent cooling. By integrating the temperature-dependent diffusion length and the process-dependent diffusion direction, we established a unified description of Ge behavior on Ag/Ge(111) substrates, in which cooling-induced Ge-enrichment at the surface reproducibly stabilizes the selective formation of monolayer germanene.
O
precursors on solid-state formation reactions of (K
Na)NbO
庄司 琢磨*; Nam, H.*; Ye, J.*; Ito, Daiki*; 高木 優香*; 米田 安宏; 永田 肇*
Journal of the American Ceramic Society, 109(3), p.e70657_1 - e70657_9, 2026/03
被引用回数：0 パーセンタイル：0.00(K,Na)NbO (KNN)系セラミックスは、優れた圧電特性を有するにもかかわらず、化学的均質性が低いことから、実用的な圧電デバイスへの応用には躊躇されてきた。本研究では、NbO前駆体の役割が製造手法によって異なり、KNNの化学的均質性と強く相関していることを軟X線吸収分光を用いて明らかにした。したがって、NbO前駆体の選択はKNN製造における支配的要因である。
早川 虹雪; 村口 正和*; 馬酔木 ゆめの*; 小島 洋一郎*; 小田 将人*; 藪田 莉名*; 石井 宏幸*; 本田 充紀
AIP Advances (Internet), 16(2), p.025337_1 - 025337_8, 2026/02
被引用回数：0 パーセンタイル：0.00風化黒雲母(WB)は粘土由来の層状鉱物であり、700C以上での溶融塩処理により熱電特性を示すようになる。本研究では、CsおよびSrのインターカレーションがWBの局所構造および電気伝導性に与える影響を調査した。WBをCsClおよび/またはSrClを含む溶融塩で処理し、得られた試料についてX線蛍光分析(XRF)、X線回折(XRD)、X線吸収微細構造(XAFS)、および四端子法による電気伝導度測定を行った。XRFによりCs/Srの取り込みが確認され、XRDにより層状構造が保持されていることが示された。XAFS解析では、Cs/Srをインターカレーションした試料において、高温下でSr-Si間距離が約
,
短縮することが明らかとなり、SrがSi-O層に近づくことが示唆された。630
860Cで測定した電気伝導度では、630780Cの範囲においてCs/Sr-WBがSr-WBより高い伝導性を示した。これらの結果から、層間イオンの再配置により伝導経路が改善されることが示され、層間構造制御が粘土系熱電材料設計における有効な手法であることが示唆された。
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
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.
松村 大樹; 石井 賢司*; 田中 裕久*; 水木 純一郎*
放射光, 39(1), p.28 - 36, 2026/01
燃料電池の開発は二酸化炭素発生抑制のためにも重要な研究課題である。中でも電極反応における酸素還元反応は、電池全体の律速過程であることから、詳しい理解が求められる。高分解能X線吸収分光法を適用し、電極反応の「その場」観察を行うことで、炭素担持白金微粒子(Pt/C)電極触媒に対して表面吸着種の電位依存観測を実施した。その結果、これまで実触媒では同定されていなかった、酸素還元反応の反応中間体としての分子状酸素吸着種の存在を、酸性環境下でもアルカリ性環境下でも見出し、酸素還元反応の理解を一歩進めることができた。
金田 美優*; 榎本 貴允*; 古林 宏之*; 深田 幸正; 狩野 旬*; 青柳 佑海人*; 藤井 達生*; 池田 直*
Japanese Journal of Applied Physics, 65(2), p.028001_1 - 028001_4, 2026/01
被引用回数：0 パーセンタイル：0.00(Physics, Applied)反射率の低い材料は光学素子などにおいて重要な役割を果たす。この研究では、安価な原料と簡易的な合成装置を用いることで、極めて低い反射率を示すホウ素をドープしたカーボンナノウオールの合成に成功した。ナノ構造と表面状態の解析から、カーボンナノウオールにホウ素をドープすることで壁の密度が高くなり、グラファイト部分の割合が低くなることが分かった。我々はナノ構造に起因する迷光効果による光吸収の機構とキャリアドープの効果による電気伝導性の向上について議論する。ホウ素をドープしたカーボンナノウオールは極めて黒い材料への実装に有益である。
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
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 
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.
上田 祐生; 小林 徹; 中村 聡志; 伴 康俊; 金田 結依; 生田目 望; Micheau, C.; 徳永 紘平; 中部 倫太郎; 金子 政志*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)溶媒抽出系における金属イオンの選択性を支配する構造要因の理解は、高レベル放射性廃棄物の分離変換プロセスを高度化する上で極めて重要である。本研究では、代表的なランタニドとしてランタン(La)とネオジム(Nd)を対象に、ニトリロトリアセトアミド(NTAamide)抽出剤のアルキル側鎖分岐度が抽出挙動に及ぼす影響を系統的に調査した。分子量は同一だがアルキル分岐度の異なる4種類の抽出剤(いずれもアミド鎖の1本が炭素数8)を用い、硝酸濃度に対する分配比を測定した。さらに、LaおよびNdの局所配位構造を拡張X線吸収微細構造(EXAFS)で解析し、有機相における超分子的凝集挙動を小角中性子散乱(SANS)で評価した。その結果、EXAFS解析から、LaおよびNdの内圏配位環境はアルキル分岐度の影響をほとんど受けないことが明らかとなった。一方、SANS解析からは、分岐の少ない抽出剤ほど低硝酸濃度で大きな凝集体を形成し、特にNdにおいては凝集体形成が抽出を促進し、難溶性錯体の沈殿を防いでいることが示された。これらの結果は、アルキル分岐度が超分子的凝集挙動を強く制御し、それが抽出挙動を支配していることを示している。本研究は、ランタニドおよびアクチニドの溶媒抽出において、選択性向上のための新しい設計概念として「ナノスケール構造制御」の可能性を示すものである。
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
被引用回数：0 パーセンタイル：0.00The optical properties of glass are strongly influenced by the redox states of trace multivalent elements. Ce
ions are commonly added to soda-lime glass to remove Fe
-induced coloration via the redox reaction Ce + Fe 
Ce
+ Fe 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
min
) 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 were examined: Fe-free, Fe-05 (0.5 mass% FeO
), and Fe-20 (2.0 mass% FeO). Above 1383 K, the Ce/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 ions, and increased for the Fe-containing glass owing to the reduction of Ce ions. The temperature dependence of the redox change (
Ce redox) showed Fe-dependent behavior: Fe-20 exhibited more pronounced Ce 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 ions, providing quantitative insights into the control of Ce-based decolorization during industrial cooling.
Nguyen, T. H. T.; 佐波 俊哉*; 山崎 寛仁*; 岩本 信之; 糸賀 俊朗*; 桐原 陽一; Lee, E.*; 杉原 健太*; 宮本 修治*; 橋本 智*; et al.
Physics Letters B, 870, p.139900_1 - 139900_8, 2025/11
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)This study has concentrated on the angular distribution of photoneutron emission on 
Ta, 
W, 
Au, Pb, and 
Bi for a 12.6 MeV linearly polarized photon beam. The angular distribution was obtained from the double differential cross-sections (DDXs), measured at the NewSUBARU-BL01 facility, and can be expressed as a function of azimuthal angle. The DDXs were divided into two distinct components based on the angular coefficient ratio: the low-energy component up to 3 MeV and the high-energy above 3 MeV. The angular distribution of the low-energy component was isotropic, whereas the high-energy component was distributed anisotropically and depended on the nuclear structure of target nuclei. The anisotropy is apparent on the spherical nuclei, but minor on the deformed ones. The comparison of angular coefficient ratios for 12.6 MeV and 16.6 MeV photon energies in the previous studies emphasized the correlation between photoneutron emission and nuclear structure.
-ordered FePt thin films studied by angle-dependent X-ray magnetic circular dichroism芝田 悟朗; 池田 啓祐*; 高梨 弘毅; 藤森 淳*; 他8名*
Applied Physics Letters, 127(14), p.142406_1 - 142406_6, 2025/10
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We have investigated the contribution of the Fe 
electrons to its magnetic anisotropy energy by angle-dependent X-ray magnetic circular dichroism at the Fe edge. By this technique, one can deduce the magnetic dipole moment 
, which represents the anisotropic spatial distribution of spin-polarized electrons, and the orbital moment anisotropy (OMA) of Fe electrons. Detected finite indicates that the spin-polarized Fe electrons are distributed preferentially in the out-of-plane direction of the films. This of Fe overwhelms the positive contribution of OMA to PMA, and reduces the PMA of -ordered FePt thin films, consistent with a previous first-principles calculation. The present result implies that a large positive contribution of the non-magnetic element Pt rather than Fe governs the PMA of -ordered FePt thin films.
谷田 肇; 小林 徹; 矢板 毅; 小畠 雅明; 福田 竜生; 伊藤 あゆみ*; 小無 健司*; 有田 裕二*
Bulletin of the Chemical Society of Japan, 98(10), p.uoaf088_1 - uoaf088_5, 2025/10
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)Structural analysis using synchrotron radiation, such as X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS), is an effective means of investigating physical properties of materials at high temperatures in order to experimentally clarify their physical properties. However, accurate temperature measurements above 2800 K are difficult, complicating the assessment of structural changes in materials. This study addresses these issues by employing a newly developed furnace capable of reaching 2800 K and performing in situ rapid XAFS and XRD measurements. These advances will improve our understanding of metal oxides at melting points and provide valuable insights into their behaviour under extreme conditions.
三浦 永祐*; 弘中 陽一郎*; 栗田 隆史*; 菖蒲 敬久; 冨永 亜希; 宮西 宏併*; 尾崎 典雅*; 渡利 威士*; 重森 啓介*
SPring-8/SACLA利用研究成果集(インターネット), 13(5), p.293 - 298, 2025/10
中空のビームパターンを持つレーザーによってレーザー駆動衝撃波を材料深部に伝搬させる手法を考案した。中空ビームパターン持つレーザーによってレーザーピーニング加工したチタン合金試料の残留応力分布を測定し、深さ方向の残留応力分布にレーザー未照射域の半径と同じ深さからプラトーが見られ、衝撃波が深部に伝搬したことが示された。この結果は2次元流体シミュレーションによっても裏付けられており、中空ビームパターンを持つレーザーによる衝撃波制御を実証すると共に、その挙動を明らかにすることができた。
斎藤 幸太郎*; 松尾 拓紀*; 米田 安宏; Ye, Z.-G*; 野口 祐二*
Journal of Applied Physics, 138(9), p.094102_1 - 094102_9, 2025/09
被引用回数：0 パーセンタイル：0.00(Physics, Applied)The phase transition behavior of relaxor ferroelectric Bi
KTiO (BKT) is investigated in ceramic from based on synchrotron radiation X-ray diffraction measurements and dielectric measurements as a function of temperature. The structural transformation from the cubic non-ergodic (NER) relaxor state to the tetragonal NER state triggers the spontaneous relaxor-to-ferroelectric phase transition. Based on the experimental observations, a temperature phase diagram of BKT is established in terms of average crystal structure and polar order.
S
studied by X-ray magnetic circular dichroismVerma, V. K.*; 芝田 悟朗; 藤森 淳*; 他8名*
Physical Review B, 112(10), p.104444_1 - 104444_8, 2025/09
被引用回数：1 パーセンタイル：41.30(Materials Science, Multidisciplinary)We have investigated the element specific magnetic characteristics of single-crystal FeCrS
using X-ray magnetic circular dichroism (XMCD). We have found that the Fe L2,3-edge XAS spectra do not exhibit clear multiplet structures, indicating strong hybridization between the Fe 3d and S 3p orbitals, leading to delocalized rather than localized electronic states. The Fe 3d and Cr 3d spin moments are antiferromagnetically coupled, consistent with the Goodenough-Kanamori rule. The orbital magnetic moments of Fe and Cr are determined to be -0.23 and -0.017 
B/ion, respectively. The large orbital magnetic moment of Fe is due to the d6 configuration under the relatively weak tetrahedra crystal field at the Fe site, and the delocalized Fe electrons maintain the orbital degree of freedom in spite of their itinerant nature. On the other hand, the octahedral crystal-field splitting of the Cr 3d level is large enough to result in the quenching of the orbital moment of the Cr ion in FeCrS.
MnCoNiCu)VO山本 孟*; 辻 卓也; 松村 大樹; 他16名*
Inorganic Chemistry, 64(34), p.17496 - 17502, 2025/08
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 (MgMnCoNiCu)VO. Although all the parent ilmenite-type compounds exhibit triclinic (
) symmetry, this compound crystallizes in a rhombohedral (
) 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.
/KNbO nanocomposite particles米田 安宏; 小林 徹; 辻 卓也; 芝田 悟朗; 竹田 幸治*; 斎藤 祐児; Khanal, G. P.*; 藤井 一郎*; 上野 慎太郎*; 佐藤 幸生*; et al.
Japanese Journal of Applied Physics, 64(8), p.08SP07_1 - 08SP07_8, 2025/08
被引用回数：1 パーセンタイル：41.30(Physics, Applied)ナノ粒子結晶の表面に別の異なる物質を成長させた複合ナノ粒子が高品位で合成できるようになってきた。このようなナノ構造体の評価には種々のスケールでの異なる評価方法を組み合わせることが効果的である。BaTiO/KNbOナノ複合粒子の種々の構造評価と電子状態評価を放射光を利用して行った。構造評価からナノ複合粒子はコア部分が100nmのBaTiOで20nmのKNbOで覆われていることが確認できた。最表面のKNbOのO-K吸収端スペクトルはバルクやナノ粒子のそれとは異なっており、複合粒子化することで化学結合状態が変化することがわかった。
-AlO(0001) for use as an adsorbent圓谷 志郎*; 本田 充紀; 滝沢 優*; 好田 誠*
Beilstein Journal of Nanotechnology (Internet), 16, p.1082 - 1087, 2025/07
被引用回数：0 パーセンタイル：0.00(Nanoscience & Nanotechnology)Graphene oxide (GO) is expected to be one of the most promising adsorbents for metal ions, including radioactive nuclides in aqueous solutions. Large-area and single-layer graphene oxide (SLGO) grown on -AlO(0001) was used as a model structure of GO since the aggregation and re-stacking of the GO sheets prevent the adequate analysis of the adsorption state. The SLGO film was obtained by oxidizing monolayer graphene grown by metal-free chemical vapor deposition on the -AlO(0001) surface, and the adsorption state was determined by surface analytical techniques. It was clarified that Cs adsorbs on oxygen functional groups by substituting with H atoms from carboxyl and hydroxy groups. It is also estimated that the weight adsorption capacity of SLGO in the 1.0 mol/L-Cs aqueous solution is as much as approximately 70 wt%. It has been demonstrated that GO has great potential to be a promising adsorbent for Cs in aqueous solutions.
