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Nagai, Takayuki; Tone, Masaya; Katsuoka, Nanako; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*
Photon Factory Activity Report 2022 (Internet), 3 Pages, 2023/00
no abstracts in English
TaS
with perpendicular magnetic anisotropy; Comparison with FeTiSShibata, Goro; Won, C.*; Kim, J.*; Nonaka, Yosuke*; Ikeda, Keisuke*; Wan, Y.*; Suzuki, Masahiro*; Koide, Tsuneharu*; Tanaka, Arata*; Cheong, S.-W.*; et al.
Photon Factory Activity Report 2022 (Internet), 2 Pages, 2023/00
no abstracts in English
Nagai, Takayuki; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*; Arima, Tatsumi*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2022/00
no abstracts in English
Miyazaki, Yasunori; Adachi, Junichi*; Masuda, Ryotaro*; Gejo, Tatsuo*; Hoshino, Masamitsu*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2021/00
no abstracts in English
Nagai, Takayuki; Shimoyama, Iwao; Okamoto, Yoshihiro; Akiyama, Daisuke*; Arima, Tatsumi*
Photon Factory Activity Report 2019 (Internet), 3 Pages, 2020/00
no abstracts in English
Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*
Photon Factory Activity Report 2018 (Internet), 2 Pages, 2019/00
no abstracts in English
Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*
Photon Factory Activity Report 2017, 2 Pages, 2018/00
no abstracts in English
Shimada, Asako; Okamoto, Yoshihiro
Photon Factory Activity Report 2017, 2 Pages, 2018/00
no abstracts in English
Iwata, Keiko; Takamizawa, Hisashi; Ha, Yoosung; Okamoto, Yoshihiro; Shimoyama, Iwao; Honda, Mitsunori; Hanawa, Satoshi; Nishiyama, Yutaka
Photon Factory Activity Report 2017, 2 Pages, 2018/00
no abstracts in English
Baba, Yuji; Shimoyama, Iwao
Photon Factory Activity Report 2017, 3 Pages, 2018/00
When a solid is heated in vacuum, a part of the surface layer desorbs as ions, which is known as "surface ionization". In this report, we present the results for surface ionization of bulk cesium chloride (CsCl). When the positive potential was applied to the sample, we found that the Cs
ions were desorbed at around 410 
C, which is lower than the melting point of CsCl (645 C). The low desorption temperature was explained by the changes in the work function of the CsCl surface. As an application, we also investigated the desorption of Cs ions from Cs-adsorbed soil. When Cs-adsorbed soil was heated at 460 C for 2 hours, about 13% of Cs was desorbed as Cs ions. The results suggest that the surface ionization would possibly be applied to the desorption of Cs from contaminated soil.
Baba, Yuji; Shimoyama, Iwao
Photon Factory Activity Report 2016, 2 Pages, 2017/00
In order to elucidate the adsorption states of radioactive Sr-90 in soil, chemical bonding states of non-radioactive strontium adsorbed on layered oxide (mica) have been investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy. Since the number of atoms in radioactive Sr-90 is extremely small, the XPS and XANES were measured under total reflection condition of the incident X-rays. The detection limit in total reflection XPS was about 150 pg/cm
, which corresponds to 300 Bq of Sr-90. The Sr 2p
core-level energy in XPS shifted to lower energy with the decrease in the thickness of Sr layer. Also, the Sr 2p 
Sr 4d
resonance energy in XANES shifts to lower energy with the decrease in the thickness. On the basis of a simple point charge model, it was elucidated that the chemical bond between Sr and mica surface becomes ionic with the decrease in the adsorbed amount of strontium.
Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro
Photon Factory Activity Report 2016, 2 Pages, 2017/00
To estimate the valence state of iron in the preparation process of iron phosphate glass frit, mixtures of ferric oxide and phosphoric acid was heated and XANES spectra of Fe-K edge was measured in this study. This report described the situation of high temperature XAFS measurement and results of this study.
Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Uehara, Akihiro*; Fujii, Toshiyuki*
Photon Factory Activity Report 2015, Part B, 2 Pages, 2016/00
To investigate the characterization damage of a borosilicate glass by a neutron irradiation, the glass sample after neutron irradiation was estimated by using the Raman spectrophotometry and the synchrotron XAFS measurement. As a result, we confirmed that the Si-O bridge structure of a borosilicate glass and the containing element valence in the glass were changed by the neutron irradiation.
Si crystals with XAS and XPSYamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka
Photon Factory Activity Report 2014, Part B, P. 112, 2015/00
In order to develop silicon-based electronic devices, metal silicides are widely studied. Information of the surface chemical states of metal silicides is important to obtain homo-epitaxial films with excellent quality. In this work, depth analysis of surface chemical states of MgSi crystals is carried by XPS. Depth analysis is also performed in XAS measurement with a partial electron yield (PEY) mode. The Si 1s XPS spectra of the cleaved surface of the MgSi crystal indicates that SiO is formed on the surface of the MgSi crystal. Here, no peak assigned to SiO structure is observed. The Si K-edge XAS spectra obtained with the PEY mode show a peak at 1843.7 eV, which can be assigned to SiO structure.
Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Honda, Mitsunori; Izumi, Toshinori; Ikeura, Hiromi*
Photon Factory Activity Report 2013, Part B, P. 546, 2014/00
The molecular orientation is one of the important factors for controlling various properties in organic semiconductor materials. Films are usually heterogeneous. Thus they exist as a mixture of microscopic domains which have a variety of orientation directions. Therefore, it is essential to observe selectively microscopic domains with different orientation direction. In this work, we have developed the photoelectron emission microscope (PEEM) system combined with the linearly polarized vacuum ultraviolet (VUV) light or synchrotron radiation (SR) X-rays. PEEM images for poly(3-hexylthiophene), P3HT thin films were observed under synchrotron X-ray irradiation with linearly polarization. In conclusion, it was found that PEEM with polarized synchrotron can be a powerful tool that gives information of molecular orientation in nano-meter scale.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Photon Factory Activity Report 2013, Part B, P. 518, 2014/00
Organic electrically conducting 
-stacked small molecules are widely regarded as promising materials for future application of low-cost and flexible nanoelectronics. Pentacene is one of the most promising organic semiconductors because of its excellent device performance. Direct measurements of electronic structures of unoccupied states of organic semiconductors lead to better understanding of mechanism of electron conduction. For probing unoccupied partial density of states (DOS), X-ray absorption spectroscopy (XAS) is commonly used, where selective excitation of the 1s core electron to the unoccupied conduction band is possible. The molecular orientation of pentacene derivative has been investigated by angle dependent XAS measurements. Electronic states were calculated by DVX
method.
Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka
Photon Factory Activity Report 2013, Part B, P. 227, 2014/00
In the present study, we examined to perform depth profiling with X-ray absorption spectroscopy (XAS) by changing electron energies (5-50 eV) for detection in order to develop non-destructive depth profiling method with chemical state information. Gold thin films (1-10 nm) deposited on Si(100) were used for specimens. The Si/Au ratios were calculated from the peak heights of each edge using observed XAS spectra. Obvious correlation between the Si/Au ratio and the electron energy is observed. With decreasing electron energy, the ratio increased significantly. This means that by reducing electron energy, information on deeper region of the surface can be obtained. These results indicate that by changing electron energies for detection, it is possible to perform non-destructive depth profiling in XAS analysis.
Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Honda, Mitsunori; Deng, J.*
Photon Factory Activity Report 2012, Part B, P. 68, 2013/00
The orientation of organic semiconducting molecules on surfaces plays a crucial role in improving the properties of electronic devices. We prepared thin films of silicon phthalocyanine dichroride (SiPcCl) on graphite spin-cast followed by heating to 350C at ambient condition. We investigate the molecular orientation of the films using angle-dependent near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy. Si 1s NEXAFS spectra for the thin films after annealing are very different each other, indicating that the corresponding reactions thus the structures of final products are different. The structures of the reaction products are estimated with the help of ab initio molecular orbital calculations that fit the observed NEXAFS spectra.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Photon Factory Activity Report 2012, Part B, P. 118, 2013/00
We have investigated the electronic property of RR-P3HT (regioregular-poly(3-hexylthiophene)) films with - stacking using sulfur K-edge X-ray absorption fine structure (XAFS) spectroscopy. It was observed that the LUMO of - stacking film is lower in energy by 0.3 eV than that of the polycrystalline powder, although these compounds are the same origin. This shift was explained that the interaction between the two molecules in co-facial leads to splitting of the LUMO level to LUMO and LUMO+1, resulting in reduced LUMO energy.
Shimoyama, Iwao; Hakoda, Teruyuki; Baba, Yuji; Sekiguchi, Tetsuhiro; Hirao, Norie; Koswattage, K.
Photon Factory Activity Report 2011, Part B, p.93_1 - 93_2, 2012/00
no abstracts in English
