HOME > プロフィール > ロク シンガプリゲ ロシャンタ クマーラ
Nanoparticles, Thin films, Amorphous, Synchrotron X-rays, X-ray diffraction, X-ray absorption fine structure spectroscopy, hard X-ray photoelectron spectroscopy , pair distribution function (PDF) , reverse Monte Carlo (RMC)
1). Characterization & computer simulation studies on transition metal nanoparticles for catalysts by high-energy X-ray diffraction coupled to pair distribution function (PDF) and reverse Monte Carlo (RMC) modelling method, extended X-ray absorption fine structure spectroscopy (EXAFS), X-ray absorption near edge structure (XANES) and hard X-ray photoelectron spectroscopy (HAXPES). 2). Synthesis, characterization & computer simulation studies of chalcogenide semiconductor glasses and melts by means of X-ray and Neutron Diffraction and EXAFS. 3). Characterization of studies on oxide thin films and amorphous thin films, by high-energy X-ray diffraction, EXAFS, anomalous X-ray scattering (AXS), and RMC method. 4). Synchrotron X-rays techniques; high resolution powder XRD, thin films XRD , high-energy XRD, small angle X-ray scattering (SAXS), AXS, EXAFS, XANES and HAXPES. 5). The correlation between functional physical properties and characteristics structure of condensed matters.
My current research focuses on characterization of nanomaterials by utilizing synchrotron X-rays. Nanotechnology, the creation of functional materials, device, and system through the control of nanoscale materials, has recently become one of most active research field. Particle with diameters in the range of 2 to 100 nm, called nanoparticles (NPs), have become a major interdisciplinary area of research during recent decades due to various applications including fuel-cell electrocatalysts and automobile exhaust gas catalysts. Because catalytic reactions occur at the surface, nanosized metal catalysts are typically used in catalysis to improve the catalytic efficiency, by increasing the surface-to-volume ratio. Recently, the Kitagawa group at Kyoto University has reported the structural identification of novel fcc-type Ru NPs and the size dependency of their more efficient catalytic activity than conventional hcp-type Ru NPs. However, the catalytic properties of NPs are strongly dependent on their atomic-scale structure, which is difficulty determined by conventional powder X-ray diffraction. In collaboration with Kitagawa group, I have previously developed a method to investigating three-dimensional atomic-scale structure of Ru nanoparticles by using HEXRD techniques coupled with pair distribution function (PDF) and reverse Monte Carlo (RMC) modelling method [Phys. Chem. Chem. Phys., 2016, 18, 30622-30629]. The RMC simulation of the atomic-scale structure of spherical particle without applying periodic boundary conditions allows the testing and refining of structure models based directly on diffraction data of spherical like nanoparticles with free surface and inhomogeneities in the atomic ordering.
- CHEN, Yanna, SAKATA, Osami, NANBA, Yusuke, LOKU SINGGAPPULIGE, Rosantha Kumara, Anli Yang, SONG, ChulHo, KOYAMA, Michihisa, Guangqin Li, Hirokazu Kobayashi, Hiroshi Kitagawa. Electronic Origin of Hydrogen Storage in MOF-covered Palladium Nanocubes Investigated by Synchrotron X-rays. COMMUNICATIONS CHEMISTRY. 1 (2018)
- Jaemyung Kim, Okkyun Seo, L. S. R. Kumara, Toshihide Nabatame, Yasuo Koide, Osami Sakata. Highly-crystalline 6 inch free-standing GaN observed using X-ray diffraction topography. CrystEngComm. 23  (2021) 1628-1633 10.1039/d0ce01572e
- Tomoya Nakatani, Sai Krishna Narayananellore, Loku Singgappulige Rosantha Kumara, Hiroo Tajiri, Yuya Sakuraba, Kazuhiro Hono. Thickness dependence of degree of B2 order of polycrystalline Co2(Mn0.6Fe0.4)Ge Heusler alloy films measured by anomalous X-ray diffraction and its impacts on current-perpendicular-to-plane giant magnetoresistance properties. Scripta Materialia. 189 (2020) 63-66 10.1016/j.scriptamat.2020.08.002
- L. S. R. Kumara, Osami Sakata, Shinji Kohara, Anli Yang, Chulho Song, Kohei Kusada, Hirokazu Kobayashi, Hiroshi Kitagawa. Structural studies of metal nanoparticles using high-energy x-ray diffraction. AIP Conference Proceedings. 2016
- チョン ジン ウォン, 桜庭 裕弥, 佐々木 泰祐, 三浦 良雄, 保井 晃, ロク シンガプリゲ ロシャンタ クマーラ, 中谷 友也, 宝野 和博. Bulk and near-interface magnetic properties of Co2Fe(Ga0.5Ge0.5) Heusler alloy explored by magnetic circular dichroism in hard x-ray photoelectron spectroscopy. 第42回 日本磁気学会学術講演会. 2018
- 坂田 修身, ロク シンガプリゲ ロシャンタ クマーラ, ソン チョルホ, 小原 真司, 吉本敏規, 吉岡聰, 小林浩和, 北川宏. Pd-Pt 固溶体ナノ粒子の局所構造と電子構造. 平成29年度 日本結晶学会年会および会員総会. 2017
- CHEN, Yanna, SAKATA, Osami, YAMAUCHI Ryosuke, YANG, Anli, LOKU SINGGAPPULIGE, Rosantha Kumara, SONG, ChulHo, MUELLER, Natalia, TAGUCHI Munetaka, INA Toshiki, KATSUYA, Yoshio, DAIMON Hiroshi, MATSUDA Akifumi, YOSHIMOTO Mamoru. Synchrotron X-ray characterization of MgxNi1-xO epitaxial thin films. EMN Summit 2017. 2017
The Japan Society of Applied Physics , Crystallographic Society of Japan , International X-ray Absorption Society , European Neutron Scattering Association