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GeFujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai-Nakata, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Sekiyama, Akira*; Tanaka, Arata*; Ebihara, Takao*; et al.
New Physics; Sae Mulli, 73(12), p.1062 - 1066, 2023/12
symmetry for anisotropic 
hybridization in the heavy-fermion superconductor CeNiGeFujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Yamasaki, Atsushi*; Higashiya, Atsushi*; Imada, Shin*; et al.
Physical Review B, 108(16), p.165121_1 - 165121_10, 2023/10
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)
Sr
CoO
(0
0.5)Matsumura, Daiju; Tsuji, Takuya; Yoshii, Kenji
Materials Chemistry and Physics, 238, p.121885_1 - 121885_5, 2019/12
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)We have conducted X-ray absorption spectroscopy study for perovskite cobaltite PrSrCoO (00.5) to understand Sr doping effect and magnetocaloric measurement for Pr
SrCoO to reveal the origin of magnetic anomaly at around 110 K. The extended X-ray absorption fine structure (EXAFS) measurements at the Co 
-edge suggest that the average valence value of Co ions increases, the interatomic distance of Co-O bonding decreases, and the local distortion of CoO
octahedron increases as Sr is doped in PrCoO. The interatomic distance of Co-O bonding shrinks more greatly for the larger doping region. No temperature dependent electronic and structural changes were observed from Co -edge X-ray absorption spectra in the whole thermal range studied (17-300 K). The magnetocaloric effect of PrSrCoO indicates the change of magnetic structure at 110 K.
Wu, H.*; Wang, Y.*; Ikeda, Atsushi; Miller, C. J.*; Waite, T. D.*
Environmental Science; Water Research & Technology, 5(8), p.1400 - 1411, 2019/08
Times Cited Count：6 Percentile：33.28(Engineering, Environmental)In this study, the distributions of iron and phosphorus species in a 1.25 m
pilot scale submerged membrane bioreactor dosed with Fe(II) salts to either the membrane chamber or the 1st anoxic chamber were determined using X-ray absorption spectroscopy (XAS) at the iron and phosphorus K-edges. Significant differences in the distribution of Fe species were evident at the commencement of dosing depending on the chamber to which Fe(II) was dosed though these differences were much less distinct by the time steady state conditions were achieved. Both the co-precipitation of P with Fe and adsorption of phosphorus to iron oxides play important roles with regard to the removal of phosphorus from the MBR supernatant with the results of this work suggesting that P removal via formation of Fe(III)-phosphate mineral species is preferred if Fe(II) is dosed to the membrane chamber rather than the 1st anoxic chamber.
Saeki, Morihisa*; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
Journal of Physical Chemistry C, 123(1), p.817 - 824, 2019/01
Times Cited Count：14 Percentile：53.94(Chemistry, Physical)Reaction kinetics of laser-induced particle formation in an aqueous solution of PdCl
was investigated by transmission electron microscope (TEM) and dispersive X-ray absorption fine structure (DXAFS). The Pd particle was generated by irradiation of nanosecond pulsed 266-nm laser. The TEM observation showed dependence of the particle size on the laser fluence and promotion of the particle growth by irradiation of high-fluence laser. The DXAFS data give us the Pd
concentration. Temporal changes of the Pd concentration analyzed based on Finke-Watzky two step mechanism. The analysis elucidates that the laser photon contributes to the reduction of the PdCl ion by the one-photon process and to the autocatalytic growth of the Pd particles by the multi-photon process.
symmetry in CeCuGe; Soft X-ray absorption and hard X-ray photoemission spectroscopyAratani, Hidekazu*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Kawada, Moeki*; Kanai, Yuina*; Yamagami, Kohei*; Fujioka, Shuhei*; Hamamoto, Satoru*; Kuga, Kentaro*; Kiss, Takayuki*; et al.
Physical Review B, 98(12), p.121113_1 - 121113_6, 2018/09
Times Cited Count：5 Percentile：25.82(Materials Science, Multidisciplinary)Shimoyama, Iwao; Baba, Yuji; Hirao, Norie*
Advances in Engineering (Internet), 1 Pages, 2018/02
The performance of organic devices largely depends on molecular orientation in organic films. Whereas micro-orientation control of organic molecules is an indispensable technology for integration of organic devices, the method has not been established. We attempted to control micro-orientation of polydimethylsilane (PDMS) thin films by deposition of PDMS on graphite substrates modified by hetero atom doping using ion beam. Polarization dependence measurements of X-ray absorption spectroscopy and molecular orbital calculations clarified that PDMS films have lying, standing, and random orientations on the non irradiated, N
-irradiated, and Ar-irradiated graphite surfaces, respectively. Furthermore, photoemission microscopy observation clarified that a PDMS film showed micro-patterns on a graphite surface with a microstructure on the order of 
m by separating N-irradiated and non irradiated areas. These results demonstrate our method is promising for micro-orientation of organic molecules.
atoms in NiFe
N (
= 1 and 3) films revealed by X-ray absorption spectroscopy and magnetic circular dichroismTakata, Fumiya*; Ito, Keita*; Takeda, Yukiharu; Saito, Yuji; Takanashi, Koki*; Kimura, Akio*; Suemasu, Takashi*
Physical Review Materials (Internet), 2(2), p.024407_1 - 024407_5, 2018/02
Times Cited Count：14 Percentile：48.52(Materials Science, Multidisciplinary)Saeki, Morihisa*; Taguchi, Tomitsugu*; Oba, Hironori*; Matsumura, Daiju; Tsuji, Takuya; Yomogida, Takumi
Denki Gakkai Kenkyukai Shiryo, Denshi Zairyo Kenkyukai (EFM-17-010
021), p.15 - 18, 2017/09
Irradiation of nanosecond pulsed UV laser into a solution of palladium ion leads to formation of palladium particles with sub-micron size particles by time-resolved X-ray absorption spectroscopy.
Gd
)Ni composed of heavy fermion CeNi and ferri-magnet GdNi through XMCD methodYano, Kazuo*; Okane, Tetsuo; Takeda, Yukiharu; Yamagami, Hiroshi; Fujimori, Atsushi; Nishimura, Katsuhiko*; Sato, Kiyoo*
Physica B; Condensed Matter, 515, p.118 - 125, 2017/06
Times Cited Count：1 Percentile：5.94(Physics, Condensed Matter)The electronic states of the three constituent elements in the crystal mixed system between CeNi and GdNi, CeGdNi, were investigated by soft X-ray magnetic circular dichroism (XMCD). Not only Gd 4f but also Ni 3d and Ce 4f electrons were magnetic and both magnetic moments of Ni and Ce were coupled anti-parallel to the direction of the Gd magnetic moment. After saturation, Ce magnetic moment decreased over 2 T and this behavior was explained by a spin-flip behavior of the Ce magnetic moment. In addition, sum rule analysis has revealed that the magnetic moments of Gd 4 f and Ni 3d electrons could retain small values of orbital magnetic moments.
Si with XPS and XASEsaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki
Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07
Times Cited Count：16 Percentile：39.42(Chemistry, Physical)XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on MgSi crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the MgSi.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Molecular Crystals and Liquid Crystals, 622(1), p.50 - 54, 2015/12
Times Cited Count：0 Percentile：0.01(Chemistry, Multidisciplinary)Organic electrically conducting 
-stacked molecules are widely regarded as promising materials for future application of nanoelectronics. Direct measurements of electronic structures of unoccupied states in 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. However, XAS cannot distinguish localized and delocalized features without comparing any theoretical approach. In this work, the core-hole-clock method in resonant Auger spectroscopy (RAS) has been applied to probe electron delocalization through the empty conduction band in the attosecond domain for the purpose of exploring electronic materials with high-speed electron transport. We will discuss some organic molecules such as pentacenes.
-YbAlB
at high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of the Physical Society of Japan, 84(11), p.114715_1 - 114715_4, 2015/11
Times Cited Count：4 Percentile：34.89(Physics, Multidisciplinary)Saito, Akinori*; Tsuji, Hiromi*; Shimoyama, Iwao; Shimizu, Kenichi*; Nishina, Yuta*
Chemical Communications, 51(27), p.5883 - 5886, 2015/04
Times Cited Count：13 Percentile：40.42(Chemistry, Multidisciplinary)no abstracts in English
-YbAlFe
B (
) at low temperatures and high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of Physics; Conference Series, 592(1), p.012020_1 - 012020_6, 2015/03
Times Cited Count：1 Percentile：43.19(Physics, Atomic, Molecular & Chemical)Valence fluctuation phenomena in rare-earth intermetallic compounds have attracted attention because the quantum criticality of the valence transition has been proposed theoretically. Recently, it was found that 
-YbAlB shows quantum criticality without tuning and has a strong mixed-valence state. In this study, we measured the magnetization curve and X-ray magnetoabsorption in -YbAlFeB (), which is a locally isostructural polymorph of -YbAlB. The magnetization and X-ray experiments were performed in fields up to 55 and 40 T, respectively. A small increase in the Yb valence was observed at fields where the magnetization curve exhibited a change in slope.
Matsumura, Daiju; Kobayashi, Toru; Miyazaki, Yuji; Okajima, Yuka*; Nishihata, Yasuo; Yaita, Tsuyoshi
Clay Science, 18(4), p.99 - 105, 2014/12
thin filmsYanagida, Tsuyoshi*; Saito, Yuji; Takeda, Yukiharu; Fujimori, Atsushi*; Tanaka, Hidekazu*; Kawai, Tomoji*
Physical Review B, 79(13), p.132405_1 - 132405_4, 2009/04
Times Cited Count：11 Percentile：45.17(Materials Science, Multidisciplinary)Creating a bipolarity of semiconductors has been a key technology to develop recent advanced semiconductor devices. Although theoretical calculation predicts the presence of ferromagnetic electron-doped manganites with doping tetravalent cations, the ferromagnetic origin in experiments has been controversial due to the lack of direct experimental evidence. Here, we investigate the ferromagnetism in (La,Ce)MnO thin films by measuring the magnetic circular dichroism in soft X-ray absorption (XMCD). The XMCD measurements clarified that the ferromagnetism is not caused by the presence of Mn but by self-hole doping for manganese.
MnNHwang, J. I.*; Ishida, Yukiaki*; Kobayashi, Masaki*; Hirata, Gen*; Takubo, Ko*; Mizokawa, Takashi*; Fujimori, Atsushi; Okamoto, Jun; Mamiya, Kazutoshi*; Saito, Yuji; et al.
Physical Review B, 72(8), p.085216_1 - 085216_6, 2005/08
Times Cited Count：64 Percentile：87.86(Materials Science, Multidisciplinary)no abstracts in English
Muramatsu, Yasuji; Ueno, Yuko*; Sasaki, Teikichi; Gullikson, E. M.*; Perera, R. C. C.*
Journal of Synchrotron Radiation, 8(2), p.369 - 371, 2002/03
Times Cited Count：2 Percentile：20.28(Instruments & Instrumentation)no abstracts in English
Muramatsu, Yasuji; Hirono, Shigeru*; Umemura, Shigeru*; Ueno, Yuko*; Hayashi, Takayoshi*; Grush, M. M.*; Gullikson, E. M.*; Perera, R. C. C.*
Carbon, 39(9), p.1403 - 1407, 2001/06
Times Cited Count：18 Percentile：58.33(Chemistry, Physical)no abstracts in English
