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Syo Matsumura Last modified date:2021.10.28



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Homepage
https://kyushu-u.pure.elsevier.com/en/persons/syo-matsumura
 Reseacher Profiling Tool Kyushu University Pure
http://www.qpn.kyushu-u.ac.jp/lab3/
Academic Degree
Doctor of Engineering
Country of degree conferring institution (Overseas)
No
Field of Specialization
Materials Science, Diffraction Physics, Electron Microscopy
Total Priod of education and research career in the foreign country
01years03months
Outline Activities
Irradiation effects, Quantitative electron microscopy
Research
Research Interests
  • Dynamical Behaviors of Materials under Irradiation
    keyword : Metal, Alloy, Ceramics, Phase Transitions, Point Defects
    1992.04.
  • Quantitative Transmission Electron Microscopy
    keyword : Electron Diffraction, Transmission Electron Microscopy, Nano-structure
    1992.04.
Current and Past Project
  • New Crossover Project Research in Nuclear Engineering
    This project promotes understanding mechanisms of grain refinement of nuclear fuels due to progress in nuclear fission. Our group carries out TEM analysis of ion-irradiated ceramics from a nanoscopic point of view.
  • RR2002 Nanotechnology Support Project:
    It offers opportunities of utilizing advanced TEMs and related facilities to researchers outside Kyushu University to promote nanotechnology research activities.
Academic Activities
Papers
1. Junsik Mun, Wei Peng, Chang Jae Roh, Sangmin Lee, Syo Matsumura, Jong Seok Lee, Tae Won Noh, Miyoung Kim, In Situ Cryogenic HAADF-STEM Observation of Spontaneous Transition of Ferroelectric Polarization Domain Structures at Low Temperatures, Nano Letters, 10.1021/acs.nanolett.1c02729, 21, 20, 8679-8686, 2021.10, Precise determination of atomic structures in ferroelectric thin films and their evolution with temperature is crucial for fundamental study and design of functional materials. However, this has been impeded by the lack of techniques applicable to a thin-film geometry. Here we use cryogenic scanning transmission electron microscopy (STEM) to observe the atomic structure of a BaTiO3 film on a (111)-SrTiO3 substrate under varying temperatures. Our study explicitly proves a structure transition from a complex polymorphic nanodomain configuration at room temperature transitioning to a homogeneous ground-state rhombohedral structure of BaTiO3 below ∼250 K, which was predicted by phase-field simulation. More importantly, another unexpected transition is revealed, a transition to complex nanodomains below ∼105 K caused by an altered mechanical boundary condition due to the antiferrodistortive phase transition of the SrTiO3 substrate. This study demonstrates the power of cryogenic STEM in elucidating structure–property relationships in numerous functional materials at low temperatures..
2. Kohei Aso, Jens Maebe, Xuan Quy Tran, Tomokazu Yamamoto, Yoshifumi Oshima, Syo Matsumura, Subpercent Local Strains Due to the Shapes of Gold Nanorods Revealed by Data-Driven Analysis, ACS Nano, 10.1021/acsnano.1c03413, 15, 7, 12077-12085, 2021.07, Analysis of subpercent local strain is important for a deeper understanding of nanomaterials, whose properties often depend on the strain. Conventional strain analysis has been performed by measuring interatomic distances from scanning transmission electron microscopy (STEM) images. However, measuring subpercent strain remains a challenge because the peak positions in STEM images do not precisely correspond to the real atomic positions due to disturbing influences, such as random noise and image distortion. Here, we utilized an advanced data-driven analysis method, Gaussian process regression, to predict the true strain distribution by reconstructing the true atomic positions. As a result, a precision of 0.2% was achieved in strain measurement at the atomic scale. The method was applied to gold nanoparticles of different shapes to reveal the shape dependence of the strain distribution. A spherical gold nanoparticle showed a symmetric strain distribution with a contraction of ∼1% near the surface owing to surface relaxation. By contrast, a gold nanorod, which is a cylinder terminated by hemispherical caps on both sides, showed nonuniform strain distributions with lattice expansions of ∼0.5% along the longitudinal axis around the caps except for the contraction at the surface. Our results indicate that the strain distribution depends on the shape of the nanomaterials. The proposed data-driven analysis is a convenient and powerful tool to measure the strain distribution with high precision at the atomic scale..
3. Sumio Iijima Wenhui Yang, Syo Matsumura, Ichiro Ohnishi, Atomic resolution imaging of cation ordering in niobium–tungsten complex oxides, Communications Materials, 10.1038/s43246-021-00128-z, 2, 24, 1-9, 2021.03, Energy dispersive X-ray emission imaging at atomic resolution is a powerful tool to solve order–disorder problems in complex metal oxide crystals, supplementing conventional X-ray or neutron diffraction. Here, we use this method, based on scanning transmission electron microscopy, to investigate cation ordering in ternary metal oxides 4Nb2O5·9WO3 and 2Nb2O5·7WO3, which have recently attracted attention as energy storage materials in lithium-ion batteries. Their crystal structures are a tetragonal tungsten bronze-type and its hybrid with a ReO3-type ‘block structure’, respectively. Our study reveals the presence of chemical ordering of metal ions in these materials, which have previously been assumed to be solid-solutions. In particular, we show that the two types of cations, Nb and W, are well ordered in their lattices, and that the Nb ions tend to occupy one third of the pentagonal channel sites. These results demonstrate that atomic resolution X-ray emission imaging is an effective alternative approach for the study of locally ordered crystal structures..
4. Kohei Kusada, Dongshuang Wu,Yusuke Nanba, Michihisa Koyama, Tomokazu Yamamoto, Xuan Quy Tran, Takaaki Toriyama, Syo Matsumura, Ayano Ito, Katsutoshi Sato, Katsutoshi Nagaoka, Okkyun Seo, Chulho Song, Yanna Chen, Natalia Palina, Loku Singgappulige, Rosantha Kumara, Satoshi Hiroi, Osami Sakata, Shogo Kawaguchi, Yoshiki Kubota, Hiroshi Kitagawa, Highly Stable and Active Solid‐Solution‐Alloy Three‐Way Catalyst by Utilizing Configurational‐Entropy Effect, Advanced Materials, 10.1002/adma.202005206, 1-7, 2021.03, Since 1970, people have been making every endeavor to reduce toxic emissions from automobiles. After the development of a three‐way catalyst (TWC) that concurrently converts three harmful gases, carbon monoxide (CO), hydrocarbons (HCs), and nitrogen oxides (NOx), Rh became an essential element in automobile technology because only Rh works efficiently for catalytic NOx reduction. However, due to the sharp price spike in 2007, numerous efforts have been made to replace Rh in TWCs. Nevertheless, Rh remains irreplaceable, and now, the price of Rh is increasing significantly again. Here, it is demonstrated that PdRuM ternary solid‐solution alloy nanoparticles (NPs) exhibit highly durable and active TWC performance, which will result in a significant reduction in catalyst cost compared to Rh. This work provides insights into the design of highly durable and efficient functional alloy NPs, guiding how to best take advantage of the configurational entropy in addition to the mixing enthalpy..
5. Satoru Yoshioka, Kazuhiro Yasuda, Syo Matsumura, Takeharu Sugiyama, Eiichi Kobayashi, Transition of Cationic Local Structures in Mg1-xNixAl2O4, Journal of Physical Chemistry C, 10.1021/acs.jpcc.0c08349, 125, 9, 5269-5277, 2021.02, In this study, cationic local structures in the series of MgAl2O4–NiAl2O4 solid solutions (Mg1-xNixAl2O4) were examined using Mg, Al, and Ni K-edge X-ray absorption near-edge structure (XANES). Theoretical calculations of XANES using the all-electron full-potential augmented plane-wave in addition to the local-orbital method were performed to investigate the transition of the cationic local structures depending on their compositions. For the calculations, the atomic coordination was studied using crystal structures of normal and ordered inverse spinels. The experimental spectra of the end members MgAl2O4 and NiAl2O4 were successfully reproduced from the theoretical spectra. Furthermore, the inversion degrees of the end members, analyzed using the calculated spectra, were consistent with previous experimental reports. The Ni2+ ions show three kinds of local structures, and their volume fractions change depending on the composition of Mg1-xNixAl2O4, whereas the Mg2+ ions show two kinds of local structures. The Al3+ ions change the local structure between tetrahedral and octahedral sites to balance the behaviors of Mg2+ and Ni2+ in the compositions. Although the analysis using XANES provides rich information, a theoretical approach is desirable for reliable and quantitative analysis of multication oxides and their disordering..
6. Dongshuang Wu, Kohei Kusada, Satoru Yoshioka, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Yanna Chen, Okkyun Seo, Jaemyung Kim, Chulho Song, Satoshi Hiroi, Osami Sakata, Toshiaki Ina, Shogo Kawaguchi, Yoshiki Kubota, Hirokazu Kobayashi, Hiroshi Kitagawa, Efficient overall water splitting in acid with anisotropic metal nanosheets, Nature Communications, 10.1038/s41467-021-20956-4, 12, 1145, 1-9, 2021.02, Water is the only available fossil-free source of hydrogen. Splitting water electrochemically is among the most used techniques, however, it accounts for only 4 % of global hydrogen production. One of the reasons is the high cost and low performance of catalysts promoting the oxygen evolution reaction (OER). Here, we report a highly efficient catalyst in acid, that is, solid-solution Ru‒Ir nanosized-coral (RuIr-NC) consisting of 3 nm-thick sheets with only 6 at.% Ir. Among OER catalysts, RuIr-NC shows the highest intrinsic activity and stability. A home-made overall water splitting cell using RuIr-NC as both electrodes can reach 10 mA cm−2geo at 1.485 V for 120 h without noticeable degradation, which outperforms known cells. Operando spectroscopy and atomic-resolution electron microscopy indicate that the high-performance results from the ability of the preferentially exposed {0001} facets to resist the formation of dissolvable metal oxides and to transform ephemeral Ru into a long-lived catalyst..
7. Junko Matsuda, Tomokazu Yamamoto, Shinji Takahashi, Hiroshi Nakanishi, Kazunari Sasaki, Syo Matsumura, In Situ TEM Investigation of Structural Changes in Ni Nanoparticle Catalysts under Gas Atmospheres: Implications for Catalyst Degradation, ACS Applied Nano Materials, 10.1021/acsanm.1c00006, 4, 2, 2175-2182, 2021.02, Ni catalysts with strong hydrogenation and dehydrogenation activities have been used to reform hydrocarbons in natural gas. In this study, microstructural changes, which relate to catalytic degradation for reforming hydrocarbons, in Ni nanocatalysts were observed in situ in oxygen, hydrogen, and methane atmospheres at elevated temperatures using an environmental transmission electron microscope. During oxidation and reduction under oxygen and hydrogen atmospheres, respectively, volumetric changes and mass transfer occurred in the Ni nanoparticle as well as in a larger Ni catalyst particle. On the other hand, the face-centered cubic (fcc) crystal structure of the Ni nanocatalysts transformed to a hexagonal close-packed (hcp) structure as the particles were heated from 250 to 350 °C in methane atmosphere at pressures of 30–40 Pa. The entire Ni nanocatalyst particle had the hcp structure at 350 °C. The spacing of close-packed planes was more than 5% wider in the hcp Ni crystals than it was in fcc Ni. We concluded that carbon and nickel solid solutions formed in the Ni particles as methane thermally decomposed to elemental carbon, which caused the transformation of the Ni crystal structure. Graphite layers appeared, surrounding the Ni particles, after the Ni transformation from fcc to hcp..
8. Xuan Quy Tran, Yoshiki Kono, Tomokazu Yamamoto, Kohei Kusada, Hiroshi Kitagawa, Syo Matsumura, Statistical Evaluation of the Solid-Solution State in Ternary Nanoalloys, Journal of Physical Chemistry C, 10.1021/acs.jpcc.0c06813 , 124, 39, 21843-21852, 2020.08, Quantitative evaluation of the alloying state in nanoalloy systems is key to understanding their functional properties in a diverse range of applications spanning from catalysis and plasmonics to biomedicine and so forth. Here, we develop a method to statistically and visually represent the sub-nanometer local compositional distribution in ternary nanoparticles (NPs) in terms of ternary histograms and kernel density estimation analysis. Further descriptive statistics is performed within the mathematical framework of compositional data analysis to account for the constant-sum constraint and positivity inherent to the nature of compositional data. The approach has been demonstrated on several conceptual particle models and real systems, namely, Pd–Rh–Ru and Ag–Au–Pd NPs, utilizing experimental X-ray energy-dispersive spectroscopy (XEDS) maps acquired from a scanning transmission electron microscope. We regard this as a useful tool for extending to other well-known configurations such as uniformly mixed solid solutions, core–shell, or phase-decomposed clusters often encountered in other nanoalloy systems. Proposed solutions to overcome common problems associated with NPs such as low X-ray counting and XEDS spectral overlapping are also presented and discussed..
9. Wenhui Yang, Xuan Quy Tran, Tomokazu Yamamoto, Satoru Yoshioka, Flora Somidin, Kazuhiro Nogita, and Syo Matsumura, Atomic locations of minor dopants and their roles in the stabilization of η-Cu6Sn5, Physical Review Materials, 10.1103/PhysRevMaterials.4.065002, 4, 6, 065002, 2020.06, Chemical modification using only small amounts of elements such as Zn, In, Sb, or Ni has proven to be an effective means to control the desirable crystal structure of hexagonal η-Cu6Sn5 over a wide thermally operating window, typically found in Pb-free Sn-based soldering or Li-ion battery anode applications. Though appealing, the underlying mechanisms on the role of these dopants remain incomplete and their atomic arrangements within the η-Cu6Sn5 lattices have not yet been experimentally determined. In the current study, we directly reveal the atomic positions of Zn, In, and Sb at the Sn sites of η-Cu6Sn5 via atomic-scale x-ray energy dispersive spectroscopy (XEDS) maps utilizing advanced Cs-corrected scanning transmission electron microscopy. The use of advanced statistical algorithms including Poisson non-local principal component analysis and lattice averaging enables the fine resolution of weak XEDS maps from trace dopant elements. Our first-principles calculations further identify the influence of dopants at these atomic sites on the overall energetics, electronic structures, as well as local bonding environments, leading to the most favorable situations for η-Cu6Sn5 stabilization..
10. Kohei Aso, Koji Shigematsu, Tomokazu Yamamoto, Syo Matsumura, Sequential transmission electron microscopy observation of the shape change of gold nanorods under pulsed laser light irradiation, Microscopy, 10.1093/jmicro/dfy136, 68, 2, 174-180, 2019.03, In situ sequential high-resolution observations were performed on gold nanorods under near-infra-red pulsed laser irradiation using a high-voltage electron microscope attached to a pulsed laser illumination system. The original nanorods were single crystals; the longer axes were oriented along [001]. Under laser light irradiation with λ = 1064 nm with an average intensity per pulse of 980 or 490 J/m2, the shape of the nanorods changed from rod to barrel surrounded by the {111} and {001} facets, while the original single-crystalline structure was maintained. The side surfaces with <110> direction were reconstructed into zig–zag fine structures consisting of narrow {111} facets. The temporal evolution of the volume and surface area during irradiation was evaluated based on the images, assuming that the particles have a rotational symmetry along their longer axes. The surface area was stepwise decreased during the shape change using pulse shots of 980 J/m2 while the volume was maintained. On the other hand, several repeated shots were required to induce the shape change when the averaged intensity was reduced to 490 J/m2 per pulse. In addition to the surface area, the volume was reduced under the latter condition during the shape change due to the evaporation of atoms. The quantitative analysis of the temporal changes indicates the heterogeneity of the atomic excitation or heating of gold nanorods induced by pulsed laser illumination..
11. Wenhui Yang, Tomokazu Yamamoto, Kohei Aso, Flora Somidin Kazuhiro Nogita, Syo Matsumura,, Atom locations in a Ni doped η-(Cu,Ni)6Sn5 intermetallic compound, Scripta Materialia, 10.1016/j.scriptamat.2018.08.020, 158, 1, 1-5, 2019.01, The present study has succeeded in direct determination of the location of dopant Ni atoms in η-(Cu,Ni)6Sn5 by aberration-corrected scanning transmission electron microscopy (STEM) including atomic-resolution imaging as well as elemental mapping by X-ray energy-dispersive spectroscopy (XEDS). The three sublattices of Sn, Cu1 and Cu2 were distinguished in atomic-resolution images observed along the [2 -1 -1 0] direction. Atomic-resolution XEDS maps have verified for the first time that the dopant Ni atoms located at the Cu2 sites in η-(Cu,Ni)6Sn5, taking advantage of the Poisson non-local principal component analysis (NLPCA) processing and the lattice-averaging procedure..
12. Takeshi Watanabe, SatoruYoshioka, TomokazuYamamoto, Hossein Sepehri-Amin, Tadakatsu Ohkubo, Syo Matsumura, Yasuaki Einaga, The local structure in heavily boron-doped diamond and the effect this has on its electrochemical properties, Carbon, 10.1016/j.carbon.2018.05.026, 137, 333-342, 2018.05, Transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS), and first principles calculations of EEL spectra were utilized to elucidate the relationship between the microscopic structure and the electrochemical properties of heavily boron-doped diamond (h-BDD). The electro-chemical properties of h-BDD containing 1 at.% and 3 at.% boron are very different. TEM observations showed that 1 at.% h-BDD consists of small densely packed diamond crystallites, while 3 at.% h-BDDcontains small voids and a graphite phase partly along the grain boundaries. The EEL spectrum of the grain interior in 1 at.% h-BDD and comparison of this with a theoretical spectrum shows that the boron atoms are mostly dispersed as single isolated substitutional atoms on diamond lattice sites in the grain interior and that only a small amount of sp2-bonded carbon is present. In contrast, in the grain interior of 3 at.% h-BDD, the boron atoms are mostly associated with nearest neighbor boron pairs, and consequently sp2-bonded carbon is formed. Thus, the local structure has a significant effect on the amount of sp2-bonded carbon. The quite different electrochemical properties of the samples are ascribed to the amount of sp2-bonding arising from the different local structures..
13. Quan Zhang, Kohei Kusada, Dongshuang Wu, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Shogo Kawaguchi, Yoshiki Kubota & Hiroshi Kitagawa, Selective control of fcc and hcp crystal structures in Au–Ru solid-solution alloy nanoparticles, Nature Communications, 10.1038/s41467-018-02933-6, 9, Article number: 510, 1-9, 2018.02, Binary solid-solution alloys generally adopt one of three principal crystal lattices—body-centred cubic (bcc), hexagonal close-packed (hcp) or face-centred cubic (fcc) structures—in which the structure is dominated by constituent elements and compositions. Therefore, it is a significant challenge to selectively control the crystal structure in alloys with a certain composition. Here, we propose an approach for the selective control of the crystal structure in solid-solution alloys by using a chemical reduction method. By precisely tuning the reduction speed of the metal precursors, we selectively control the crystal structure of alloy nanoparticles, and are able to selectively synthesize fcc and hcp AuRu3 alloy nanoparticles at ambient conditions. This approach enables us to design alloy nanomaterials with the desired crystal structures to create innovative chemical and physical properties..
14. Kohei Aso, Koji Shigematsu, Tomokazu Yamamoto, Syo Matsumura, Detection of picometer-order atomic displacements in drift-compensated HAADF-STEM images of gold nanorods, Microscopy, 10.1093/jmicro/dfw018, 65, 5, 391-399, 2016.09.
15. S. Takaki, kazuhiro Yasuda, Tomokazu Yamamoto, Syo Matsumura, Norito Ishikawa, Atomic structure of ion tracks in Ceria, Nuclear Instruments and Methods in Physics Research B, 10.1016/j.nimb.2013.10.077, 326, 140-144, 2014.05, We have investigated atomic structure of ion tracks in CeO2 irradiated with 200 MeV Xe ions by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM observations under inclined conditions showed continuous ion tracks with diffraction and structure factor contrast, and the decrease in the atomic density of the ion tracks was evaluated to be about 10%. High resolution STEM with high-angle annular dark-field (HAADF) technique showed that the crystal structure of the Ce cation column is retained at the core region of ion tracks, although the signal intensity of the Ce cation lattice is reduced over a region 4–5 nm in size. Annular bright field (ABF) STEM observation has detected that the O anion column is preferentially distorted at the core region of ion tracks within a diameter of 4 nm. The core region of ion track in CeO2 is determined to contain a high concentration of vacancies or small vacancy clusters and to generate interstitials in surrounding regions..
16. Nao Sumimoto, Koichiro Nakao, Tomokazu Yamamoto, Syo Matsumura, kazuhiro Yasuda, Yasuro Niidome, In situ observation of structural transformation of gold nanorods under pulsed laser irradiation in an HVEM , Microscopy, 10.1093/jmicro/dfu012, 63, 4, 261-268, 2014.04, A pulsed laser light illumination system was attached to a high-voltage electron microscope (HVEM) for in situ observation of light-induced behaviors of nano objects. The wavelength λ of emitted laser pulses was 1064, 532 or 266 nm, and the pulse duration was 6–8 ns. Using this combined HVEM system, we observed the deformation behavior of gold nanorods irradiated by a pulsed laser (λ = 1064 nm) at an intensity of 310 J m−2 pulse or higher. A single shot of pulsed laser reduced the aspect ratio of the gold nanorods from 5 to a much smaller value. The extent of the reduction increased at higher laser intensities. However, at 310 J m−2 pulse−1, additional pulsed shots induced limited further deformation. The mean aspect ratio approximated to 2.5 even after irradiation with 7 pulses (total fluence exceeding 2 MJ m−2). In situ high resolution transmission electron microscopy (HRTEM) observation revealed that deformation was accompanied by total atomic restructuring of the nanorod interiors..
17. kazuhiro Yasuda, M. Etoh, K. Sawada, Tomokazu Yamamoto, Kazufumi Yasunaga, Syo Matsumura, Norito Ishikawa, Defect formation and accumulation in CeO2 irradiated with swift heavy ions, Nuclear Instruments and Methods in Physics Research B, 10.1016/j.nimb.2013.04.069, 314, 185-190, 2013.11, We have investigated microstructure evolution in CeO2 irradiated with 210 MeV Xe ions by using transmission electron microscopy to gain the fundamental knowledge on radiation damage induced by fission fragments in nuclear fuel and transmutation target. Analysis on the accumulation of ion tracks has revealed an influence region to recover pre-existing core damage regions of ion tracks to be 8.4 nm in radius. Cross section observations showed that high-density electronic excitation induces both ion tracks and dislocation loops. At high fluences of 1.5 × 1019 and 1 × 1020 ions m−2, depth-dependent microstructure was developed with radiation-induced defects of ion tracks, dislocation loops (dot-contrast) and line dislocations. Formation of sub-divided small grains was found at shallow depth at a fluence of 1 × 1020 ions m−2. The microstructure evolution was discussed in terms of the accumulation of interstitials due to significant overlap of high density electronic excitation..
18. M. Timpel, N. Wanderka, R. Schlesiger, T. Yamamoto, N. Lazarev, D. Isheim, G. Schmitz, Syo Matsumura, J. Banhart, Sr–Al–Si co-segregated regions in eutectic Si phase of Sr-modified Al–10Si alloy, Ultramicroscopy, dx.doi.org/10.1016/j.ultramic.2012.10.006, 132, 216-221, 2013.09, The addition of 200 ppm strontium to an Al–10 wt% Si casting alloy changes the morphology of the eutectic silicon phase from coarse plate-like to fine fibrous networks. In order to clarify this modification mechanism the location of Sr within the eutectic Si phase has been investigated by a combination of high-resolution methods. Whereas three-dimensional atom probe tomography allows us to visualise the distribution of Sr on the atomic scale and to analyse its local enrichment, transmission electron microscopy yields information about the crystallographic nature of segregated regions. Segregations with two kinds of morphologies were found at the intersections of Si twin lamellae: Sr–Al–Si co-segregations of rod-like morphology and Al-rich regions of spherical morphology. Both are responsible for the formation of a high density of multiple twins and promote the anisotropic growth of the eutectic Si phase in specific crystallographic directions during solidification. The experimental findings are related to the previously postulated mechanism of “impurity induced twinning”..
19. Kazu Suenaga, Toshiya Okazaki, Eiji Okunishi, Syo Matsumura, Detection of photons emitted from single erbium atoms in energy-dispersive X-ray spectroscopy, Nature Photonics, 10.1038/nphoton.2012.148, 6, 8, 545-548, 2012.08, The detection of photons emitted from single quantum objects is highly desirable for the diagnosis of nanoscale devices using microscopes. An extremely tiny probe (∼0.1 nm) with high current recently became available for aberration-corrected scanning transmission electron microscopy, and it is possible for individual atoms in nanoscale devices to be excited using such a highly focused probe1–3. Here, we demonstrate the successful
detection of characteristic X-ray signals from single erbium atoms using energy-dispersive X-ray spectroscopy. The intensities of the erbium L and M lines from a single erbium atom were extremely weak in comparison to the N edge of electron energy-loss spectroscopy, demonstrating the intrinsic difficulty in sensing single atoms using X-ray spectroscopy.
Nevertheless, this work will certainly help in the advance towards obtaining X-ray spectra from single atoms and to evaluate the fluorescence yield on a single-atom basis..
20. M. Timpel, N. Wanderka, R. Schlesiger, T. Yamamoto, N. Lazarev, D. Isheim, G. Schmitz, Syo Matsumura, J. Banhart, The role of strontium in modifying aluminium–silicon alloys
, Acta Materialia, http://dx.doi.org/10.1016/j.actamat.2012.03.031, 60, 9, 3920–3928, 2012.05, Small amounts of strontium can transform the morphology of the eutectic silicon phase present in Al–Si casting alloys from coarse plate-like to fine fibrous networks. In order to understand this industrially important but hitherto insufficiently understood effect, the strontium distribution was studied in atomic resolution by atom probe tomography and in nanometre resolution by transmission electron microscopy. The combined investigations indicate that Sr co-segregates with Al and Si within the eutectic Si phase. Two types of segregations were found: (i) nanometre-thin rod-like co-segregations of type I are responsible for the formation of multiple twins in a Si crystal and enable its growth in different crystallographic directions; (ii) type II segregations come as more extended structures, restrict growth of a Si crystal and control its branching. We show how Sr enables both kinds of mechanisms previously postulated in the literature, namely “impurity-induced twinning” (via type I) and growth restriction of eutectic Si phase (via type II)..
21. H. Unno, Y. Sato, S. Toh, N. Yoshinaga, S. Matsumura, Microstructures and electrical properties of TiO2-doped Al2O3 ceramics, Journal of Electron Microscopy, Volume 59, Pages S107-S115, 2010.08.
22. M. Shirai, K. Tsumori, M. Kutsuwada, K. Yasuda, S. Matsumura , Morphological change in FePt nanogranular thin films induced by swift heavy ion irradiation, Nuclear Instruments and Methods in Physics Research Section B, Volume 267, Issue 10, Pages 1787-1791
, 2009.05.
23. Kousuke Kimura, Satoshi Hata, Syo Matsumura and Takao Horiuchi, Dark-field transmission electron microscopy for a tilt series of ordering alloys: toward electron tomography, Journal of Electron Microscopy, 10.1093/jmicro/dfi060, 54, 4, 373-377, 54 [4], 373-377, (2005), 2005.12.
24. K. Kaneko, S. Matsumura, K. Ikematsu, Y. Kato, Y. Tomokiyo, M. Watanabe, T. Masumoto, Quantitative electron microscopy of FePt nano-crystallites in amorphous Al2O3 matrix, Scripta Materialia, 10.1016/S1359-6462(02)00627-9, 48, 7, 915-920, 48, 915-920, 2003.08.
25. C. Abromeit, S. Matsumura, Kinetics of antiphase domain boundaries during an L12 order-disorder phase transformation: a Monte Carlo simulation, Philosophical Magazine A, 10.1080/01418610210138950, 82, 11, 2287-2302, 82, 2287-2302, 2002.08.
26. S. Matsumura, Y. Tanaka, Y. Koga, K. Oki, Concurrent ordering and phase separation in the vicinity of the metastable critical point of order-disorder transition in Fe-Si alloys, Materials Science and Engineering A, 10.1016/S0921-5093(00)01874-8, 312, 1-2, 284-292, 312, 284-292, 2001.05.
Presentations
1. Syo Matsumura, Kohei Aso, Tomokazu Yamamoto, HAADF-STEM study of local lattice strain in gold nanoparticles, Int’l Conf. Nanoscience and Nanotechnology (ICONN2020), 2020.02.
2. Syo Matsumura, Wenhui Yang, Tomokazu Yamamoto, Flora Somidin, Kazuhiro Nogita, STEM-XEDS Study of Atom Locations of Dopant Elements in Cu6Sn5 Intermetallic Compounds, 12th AsiaーPacific Microscopy Conference (APMC2020), 2020.02.
3. Syo Matsumura, Nao Sumimoto, Tomokazu Yamamoto, kazuhiro Yasuda, High Resolution Electron Microscope Observation of Gold Nanorods under Irradiation with Pulsed Laser Light, The 8th International Conference on Advanced Materials Processing (ICAMP-8) , 2014.07.
4. Syo Matsumura, Tomokazu Yamamoto, kazuhiro Yasuda, Seiya Takaki, Transmission Electron Microscopy Study of Defect Formation and Accumulation in Ceramic Oxides Irradiated with Swift Heavy Ions, 2012 MRA Fall Meeting, 2012.11.
Membership in Academic Society
  • The Musicological Society of Japan
Educational
Educational Activities
Graduate School of Engineering, Department of Applied Quantum Physics and Nuclear Enginering:
(classes) Materials Science for Energy Systems I, II, Basic Principles of Diffraction Physics

International Special Course on Environmental Systems Engineering (PhD Course)
(class) CL5

School of Engineering, Department of Energy Science
(classes) Statistical Mechanics, Basic I

General Science Course,
(class) Basic Principles of Waves
Other Educational Activities
  • 2012.01, Faculty Opponent to phD thesis at Stockholm University.
  • 2008.05, Distingushed Lecture of the year, Kyushu University.
Social
Professional and Outreach Activities
Leader: RR2002 Nanotechnology Support Project
Leader: Nanotechnology innovation network project.