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Journal Articles

Time-resolved observation of structure change in real time by using X-ray absorption fine structure spectroscopy with dispersive optics

Matsumura, Daiju; Kato, Kazuo*

Hoshako, 34(1), p.3 - 11, 2021/01

no abstracts in English

Journal Articles

Synchrotron radiation real-time photoelectron spectroscopy study on adsorption reactions of oxygen molecule at semiconductor surfaces

Yoshigoe, Akitaka

Hoshako, 32(4), p.185 - 198, 2019/07

Synchrotron radiation photoelectron spectroscopy is a beneficial technique for precise analysis of chemical states of solid surfaces. Owing to its high luminosity, it ensures availability of termed synchrotron radiation real-time photoelectron spectroscopy which enables "${it in situ}$" observation of chemical reactions with gas molecules occurring at surfaces. In this review, oxygen adsorption reactions in the oxidation of silicon single crystal surfaces are focused. Through the demonstration of our research, the usefulness of synchrotron radiation real-time photoelectron spectroscopy to study molecular adsorption reactions at solid surfaces is briefly described and the future perspective would also be shown.

Journal Articles

Exploring the development of cesium removal processes via nanoscale chemical state analysis of cesium-containing clay minerals; Application of soft X-ray synchrotron radiation photoelectron microscopy to observe insulating materials

Yoshigoe, Akitaka

Hoshako Riyo No Tebiki, p.130 - 138, 2019/02

The educational book on next-generation synchrotron radiation usage is partially written. This book is being planned by several professors at Tohoku University. In this book, the contents which have already reported in our recent paper [Appl. Phys. Lett. 112 (2018) 021603.] are mainly written. The future perspective on photoemission electron microscopy using next generation synchrotron radiation and its possibility to analyze environmental samples and insulating functional materials are also described.

Journal Articles

Synchrotron radiation based X-ray absorption study for upgrade of nuclear waste vitrification technique

Okamoto, Yoshihiro; Nagai, Takayuki; Shiwaku, Hideaki

Hoshako, 31(4), p.274 - 280, 2018/07

As a method for disposal of nuclear waste, the use of vitrification technique is very promising. In this technique, many kinds of elements should be involved stably in the glass and chemical state of these elements in the glass must be confirmed in order to guarantee stability of the glass. We have used synchrotron based X-ray absorption fine structure (XAFS) technique, in which the element selectivity is utilized, to obtain the chemical state of each element in many kinds of simulated glass samples. In addition, imaging XAFS technique has been used to clarify correlation between constituent elements. We are going to contribute to research and development of the vitrification technique by using synchrotron radiation based XAFS analyses. In this article, we introduce results of the high energy XAFS of high temperature slag samples, the imaging study of high temperature borosilicate glass samples and the imaging XAFS analysis of platinum group metals in the borosilicate glass samples.

Journal Articles

Development of the atomic pair-distribution function analysis by synchrotron X-ray

Yoneda, Yasuhiro

Hoshako, 28(3), p.117 - 123, 2015/05

Atomic pair-distribution function (PDF) analysis are the method which visualizes the structure from a short- to middle-range order. It has been applied to amorphous materials and liquids in the past. It could also be used now for the crystallized materials by using a synchrotron X-ray and a pulsed neutron facilities. There is some deviation between the average structure obtained by the traditional crystal structure analysis, and the local structure caused by the domain configuration in ferroelectrics, magnetic materials, hydrogen-storage materials, etc. The PDF analysis is attracted as the method bridging the local and the average structure. The outline of development of research technique and applications are reviewed about the PDF analysis using synchrotron X-ray.

Journal Articles

Structure refinement for the $$alpha$$-$$varepsilon$$ transition of iron by using EXAFS

Ishimatsu, Naoki*; Sata,Yusuke*; Maruyama, Hiroshi*; Watanuki, Tetsu; Kawamura, Naomi*; Mizumaki, Masaichiro*; Irifune, Tetsuo*; Sumiya, Hitoshi*

Hoshako, 28(1), p.3 - 11, 2015/01

no abstracts in English

Journal Articles

Cs adsorption mechanism on clay minerals based on material sciences using synchrotron radiation and first principle calculation

Yaita, Tsuyoshi; Kobayashi, Toru; Ikeda, Takashi; Matsumura, Daiju; Machida, Masahiko; Okumura, Masahiko; Nakamura, Hiroki

Hoshako, 27(6), p.315 - 322, 2014/11

no abstracts in English

Journal Articles

Crystal structural analysis of solid oxide fuel cells using the synchrotron X-ray and neutron diffraction method

Ito, Takanori*; Igawa, Naoki; Homma, Tetsuo*

Supuringu-8 No Kokido Hoshako O Riyoshita Gurin Enerugi Bunya Niokeru Denchi Kaihatsu, p.104 - 112, 2014/02

Functional materials consist of many elements and therefore have complex crystal structure. Synchrotron X-ray and neutron scattering facilities are powerful tools to investigate the crystal structural information of those materials. Here we make an introduction to the crystal analysis method by the synchrotron X-ray and neutron diffraction applying to the solid oxide fuel cells.

Journal Articles

Syntheses of novel metal hydrides under high pressure and high pressure with the aid of ${it in-situ}$ synchrotron radiation X-ray diffraction measurement

Saito, Hiroyuki; Takagi, Shigeyuki*; Aoki, Katsutoshi; Orimo, Shinichi*

Hoshako, 27(1), p.10 - 19, 2014/01

no abstracts in English

Journal Articles

Superfluorescence observed using an EUV-FEL

Harries, J.; Shigemasa, Eiji*

Hoshako, 26(6), p.327 - 334, 2013/11

We report on the first observation of superfluorescence (collective spontaneous emission) at an FEL, using the EUV free-electron laser and a high number density helium gas cell. We introduce superfluorescence as an example of quantum optics experiments which can be performed at the new generation of light sources, and discuss future prospects, including the extension to shorter wavelengths.

Journal Articles

Precious-metal-free automotive catalyst in the elements science and technology project

Nishihata, Yasuo; Matsumura, Daiju

Hoshako, 26(2), p.57 - 63, 2013/03

Self-regeneration of the intelligent catalyst as an automotive catalyst was observed by ${it in-situ}$ XAFS. Palladium nano-particles in catalytic reaction were also observed to elucidate the difference in activity between the intelligent catalyst and the conventional one. Copper has been investigated as a candidate to replace precious metals since the first-principle theory predicts an active copper surface for NO dissociation. The redox property of Cu turned into a similar property of precious metals by managing the interaction between Cu particles and a substrate. The conversion efficiency of Ni-Cu alloy particles increased than each element alone. The Ni was oxidized faster than the Cu so as to maintain a metallic surface of Cu. These properties of Cu were incorporated into new design of a Cu catalyst, which has achieved high catalytic activity with the regular operation of engine in the beginning.

Journal Articles

Phase retrieval from a sparse scattering pattern for single molecular structural analysis

Kono, Hidetoshi; Ikeda, Shiro*

Hoshako, 26(1), p.38 - 43, 2013/01

A new strong, short-pulse and coherent X-ray light source, which has been built at SPring8, is expected to achieve a single molecular imaging. With this 109 times brighter light than that of the current synchrotrons, we have to measure the diffraction within a few femto-second before the molecule is destroyed due to the radiation damage. Thus, the obtained diffraction pattern will be very sparse. We have recently developed a phase retrieval method based on the Bayesian statistics that is applicable for such a sparse diffraction pattern. In this article, we introduce the method.

Journal Articles

Pressure-induced formation of intermediate-valence quasicrystalline systems in Yb-based alloys

Watanuki, Tetsu; Kawana, Daichi*; Machida, Akihiko; Tsai, A. P.*

Hoshako, 25(3), p.176 - 183, 2012/05

Quasiperiodic intermediate-valence systems were prepared by applying pressure to Yb-based quasicrystals. In these systems, each quasiperiodic lattice point has a charge degree of freedom. Synchrotron radiation X-ray absorption spectroscopy experiments near the Yb $$L_3$$-edge demonstrate that the Yb valence in a Cd-Yb icosahedral quasicrystal increases continuously upon compression from a divalent state at ambient pressure and reaches 2.33 at 31.7 GPa, where the quasiperiodically arranged Yb ions take a valence fluctuation state. For the case of a Cd-Mg-Yb icosahedral quasicrystal, the Yb valence reaches a value of 2.71 at 57.6 GPa. By following the trend of Yb-based intermediate-valence crystalline compounds, this large valence increase suggests that the 4f electron system in this quasicrystal varies from a valence fluctuation regime to a strong correlated electron regime.

Journal Articles

High-sensitive, high-resolution, and wide-field-of-view image sensor for EUV-FEL

Fukuda, Yuji; Faenov, A.*; Pikuz, T.*

Hoshako, 23(5), p.308 - 312, 2010/09

We have characterized the performance of LiF crystal as an imaging sensor for extreme ultraviolet free electron laser (EUV-FEL). We found that the LiF crystal could register a single shot image of various materials in a wide field of view with high spatial resolution and high dynamic range. Detailed structure of focused spot image of single shot EUV-FEL was measured using the LiF crystal. It is found that a crater appears on a surface of LiF in one shot.

Journal Articles

Evaluation of stress and strain using synchrotron radiation

Tanaka, Keisuke*; Suzuki, Kenji*; Akiniwa, Yoshiaki*; Shobu, Takahisa

Hoshako Ni Yoru Oryoku To Hizumi No Hyoka, 238 Pages, 2009/10

no abstracts in English

Journal Articles

Nature of magnetic coupling between Mn ions in as-grown Ga$$_{1-x}$$Mn$$_{x}$$As studied by X-ray magnetic circular dichroism

Takeda, Yukiharu; Kobayashi, Masaki*; Okane, Tetsuo; Okochi, Takuo*; Okamoto, Jun*; Saito, Yuji; Kobayashi, Keisuke*; Yamagami, Hiroshi; Fujimori, Atsushi*; Tanaka, Arata*; et al.

Hoshako, 22(4), p.202 - 209, 2009/07

no abstracts in English

Journal Articles

Soft X-ray angle resolved photoelectron spectroscopy study of heavy Fermion superconductor UPd$$_2$$Al$$_3$$

Fujimori, Shinichi; Saito, Yuji; Okane, Tetsuo; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika

Hoshako, 22(1), p.11 - 19, 2009/01

We have performed angle-resolved photoemission experiments in soft X-ray region (SX-ARPES) for the heavy Fermion superconductor UPd$$_2$$Al$$_3$$ to observe its band structure. At low temperatures (20 K), renormalized quasi-particle bands were observed in the vicinity of the Fermi level. The overall structure of ARPES spectra including strongly dispersive bands on the higher binding energy sides is fairly well explained by the band structure calculation treating U 5f electrons as being itinerant. This suggests that itinerant description is a reasonable approach to understand their electronic properties at low temperatures. On the other hand, at high temperatures (100 K), the quasi-particle bands moved toward higher binding energies, and became less dispersive. This suggests that the U 5f electrons change their character from itinerant one at low temperatures to localized one at high temperatures.

Journal Articles

Devil's flower resulting from a successive charge disproportionation of NaV$$_{2}$$O$$_{5}$$; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Hoshako, 21(2), p.87 - 96, 2008/03

Devil's flower has been found in a temperature-pressure phase diagram of NaV$$_{2}$$O$$_{5}$$, which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaV$$_{2}$$O$$_{5}$$. The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.

Journal Articles

A Report of ERL-2007 Workshop

Hajima, Ryoichi; Sakanaka, Shogo*

Hoshako, 20(4), p.263 - 265, 2007/07

no abstracts in English

Journal Articles

Theory of resonant inelastic X-ray scattering in transition-metal compounds

Nomura, Takuji; Igarashi, Junichi*; Takahashi, Manabu*

Hoshako, 20(3), p.171 - 179, 2007/05

Recently, electronic excitation spectra have been observed in strongly correlated electron systems such as transition-metal compounds, by utilizing the highly brilliant synchrotron radiation. Among them, momentum dependent excitation spectra are observed in resonant inelastic X-ray scattering (RIXS) experiments at the transition-metal absorption $$K$$-edge in the hard X-ray regime. The microscopic theory of RIXS constructed recently by the present authors is explained. An essential point is that RIXS spectrum is closely related to the dynamical density correlation function of correlated transition-metal $$d$$ electrons. Spectral shapes and momentum dependence observed in several transition-metaloxides are semiquantitatively explained.

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