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Journal Articles

Dynamic of organic species in organo-clay/polypropyrene composite by quesi-elastic neutron scattering

Fukushima, Yoshiaki*; Yamada, Takeshi*; Tamura, Kenji*; Shibata, Kaoru

Applied Clay Science, 155, p.15 - 19, 2018/04

 Times Cited Count:4 Percentile:31.92(Chemistry, Physical)

Dynamics of a fluoromica (ME100) cation exchanged for dioctadecyl dimethyl ammonium ion (DODA$$^{+}$$)/ polypropylene composite was analyzed by quasi elastic neutron scattering (QENS), besides XRD and DSC. The QENS spectra for the DODA-ME100 at low Q=2.75 nm$$^{-1}$$ were not changed even at temperature higher than 445 K, the melting point of DODA$$^{+}$$. The results suggested the long range ($$>$$ 2 nm) molecular motions in interlayer space are restricted due to the rigid silicate layers and the strong electrostatic interaction between DODA$$^{+}$$ and the ME100. Elastic intensity scan results suggested that a little amount of motion of the polymer chains in the composite was also restricted in the molten state at 445 K. The QENS is expected to be one of the useful tools for studying the composite materials.

Journal Articles

Electronic structure of BaTiO$$_{3}$$ using resonant X-ray emission spectroscopy at the Ba-L$$_{3}$$ and Ti K absorption edges

Yoshii, Kenji; Yoneda, Yasuhiro; Jarrige, I.*; Fukuda, Tatsuo; Nishihata, Yasuo; Suzuki, Chikashi; Ito, Yoshiaki*; Terashima, Takahito*; Yoshikado, Shinzo*; Fukushima, Sei*

Journal of Physics and Chemistry of Solids, 75(3), p.339 - 343, 2014/03

 Times Cited Count:7 Percentile:36.72(Chemistry, Multidisciplinary)

We have studied the electronic properties of ferroelectric BaTiO$$_{3}$$ using two complementary bulk-sensitive spectroscopic probes, resonant X-ray emission spectroscopy (RXES) and X-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS). Contrary to a previous study, we found no temperature change of a PFY-XAS spectrum at the Ba L$$_{3}$$ edge between room temperature and 150$$^{circ}$$C. This result is not supportive of the possible presence of the displacement around Ba$$^{2+}$$ at the Curie temperature. RXES spectra were measured at the Ti K edge for BaTiO$$_{3}$$, along with SrTiO$$_{3}$$ and La-doped metallic SrTiO$$_{3}$$. The photon energy of the emission peak is found to be nearly constant throughout the absorption edge for all three compounds. We deduce the Ti 3d states to have a delocalized character, in contrast with the Ba 5d states, a property which is consistent with the proposed scenario of the formation of electric dipoles in BaTiO$$_{3}$$.

Journal Articles

Probing the Ba 5d states in BaTiO$$_{3}$$ and BaSO$$_{4}$$; A Resonant X-ray emission study at the Ba-L$$_{3}$$ edge

Yoshii, Kenji; Jarrige, I.; Suzuki, Chikashi; Matsumura, Daiju; Nishihata, Yasuo; Yoneda, Yasuhiro; Fukuda, Tatsuo; Tamura, Kazuhisa; Ito, Yoshiaki*; Mukoyama, Takeshi*; et al.

Journal of Physics and Chemistry of Solids, 73(9), p.1106 - 1110, 2012/09

 Times Cited Count:11 Percentile:47.94(Chemistry, Multidisciplinary)

We have directly probed the Ba 5d states in the ferroelectric barium titanate BaTiO$$_{3}$$ using resonant X-ray emission spectroscopy (RXES) and X-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS) at the Ba-L$$_{3}$$ edge. The results are compared with those of the non-ferroelectric BaSO$$_{4}$$. While the RXES spectra point to a localized character for the Ba 5d states in both compounds, the main peak of the PFY-XAS spectrum, corresponding to the dipolar transitions from 2p to 5d, is found to be significantly broader for BaTiO$$_{3}$$ than for BaSO$$_{4}$$. On the basis of band structure calculations, this broadening is ascribed to strong hybridization between the unoccupied Ba 5d and O 2p states in the ferroelectric. This suggests that the hybridization between the conduction states of the Ba$$^{2+}$$ and O$$^{2-}$$ ions, and not only Ti$$^{4+}$$ and O$$^{2-}$$, plays a central role in determining the electronic structure of BaTiO$$_{4}$$.

Journal Articles

Resonant inelastic X-ray scattering at Ba-L$$_{3}$$ edge in BaTiO$$_{3}$$

Yoshii, Kenji; Jarrige, I.; Matsumura, Daiju; Nishihata, Yasuo; Suzuki, Chikashi; Ito, Yoshiaki*; Mukoyama, Takeshi*; Tochio, Tatsunori*; Shinotsuka, Hiroshi*; Fukushima, Sei*

Japanese Journal of Applied Physics, 50(9), p.09NE03_1 - 09NE03_4, 2011/09

 Times Cited Count:2 Percentile:10.82(Physics, Applied)

Resonant X-ray inelastic scattering experiments have been performed at the Ba-L$$_{3}$$ edge in ferroelectric BaTiO$$_{3}$$ using synchrotron radiation at the BL15XU of SPring-8. An X-ray absorption spectrum of this material was found to be broader than non-ferroelectric BaSO$$_{4}$$. Molecular orbital calculations showed the formation of Ba-O bands in BaTiO$$_{3}$$, suggesting an important role of the Ba-O hybridization in the ferroelectric transition of this material. X-ray emission spectra at the edge showed a localized character of Ba-5d orbitals in BaTiO$$_{3}$$ in spite of the hybridization with O-3p. A few possible applications of the measurement will be also discussed.

Oral presentation

Oral presentation

Probing the Ba 5d states in BaTiO$$_{3}$$ and BaSO$$_{4}$$; A Resonant X-ray emission study at the Ba-L$$_{3}$$ edge

Yoshii, Kenji; Jarrige, I.; Matsumura, Daiju; Nishihata, Yasuo; Suzuki, Chikashi; Ito, Yoshiaki*; Mukoyama, Takeshi*; Tochio, Tatsunori*; Shinotsuka, Hiroshi*; Fukushima, Sei*

no journal, , 

We have directly probed the Ba 5d states in the ferroelectric BaTiO$$_{3}$$ by resonant X-ray emission spectroscopy (RXES) and X-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS) at the Ba-L$$_{3}$$ edge. The results are compared with those of the non-ferroelectric barium sulfate BaSO$$_{4}$$. While the RXES spectra point to a localized character for the Ba 5d states in both compounds, the main peak of the PFY-XAS spectrum is found to be significantly broader for BaTiO$$_{3}$$ than for BaSO$$_{4}$$. On the basis of band structure calculations, this broadening is ascribed to strong hybridization between the unoccupied Ba 5d and O 2p states in the ferroelectric phase. This suggests that the hybridization between the conduction states of the Ba$$^{2+}$$ and O$$^{2-}$$ ions, and not only Ti$$^{4+}$$ and O$$^{2-}$$, plays some roles in the occurrence of ferroelectricity in BaTiO$$_{3}$$.

Oral presentation

Quasielastic scattering of water in mesoporous silica studied by Si backscattering spectrometer DNA

Yamada, Takeshi*; Shibata, Kaoru*; Takahashi, Nobuaki; Kamazawa, Kazuya*; Kawakita, Yukinobu; Fukushima, Yoshiaki*; Nakajima, Kenji; Kambara, Wataru; Inamura, Yasuhiro; Nakatani, Takeshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Basic data acquisitions for development of remote decontamination techniques, 1; Project outline and basic data acquisition plan

Yaita, Yumi*; Sakai, Hitoshi*; Endo, Hiroshi*; Otani, Tomomi*; Takahashi, Yoshiaki*; Oikawa, Kageharu*; Murata, Hirotoshi*; Fukushima, Mineo; Kawatsuma, Shinji

no journal, , 

no abstracts in English

Oral presentation

Resonant X-ray emission at Ti K and Ba L$$_{3}$$ edges in BaTiO$$_{3}$$

Yoshii, Kenji; Yoneda, Yasuhiro; Jarrige, I.*; Suzuki, Chikashi; Ito, Yoshiaki*; Yoshikado, Shinzo*; Fukushima, Sei*

no journal, , 

We have observed the electronic structures of ferroelectric BaTiO$$_{3}$$ by means of resonant X-ray emission spectroscopy (RXES) at Ba-L$$_{3}$$ and Ti-K edges. High- resolution X-ray absorption spectra using RXES at Ba-L$$_{3}$$ edge showed no temperature dependence below and above the Curie temperature. This result is different from the previous data, in which the change of spectral shape suggested the displasive mechanism. Thus, a careful reexamination is needed in future. The RXES measurements at Ti-K edge showed the presence of fluorescence peak only, indicating that the excited electron is raplidly delocalied. This suggests the strong covalency between Ti and O and is consistent with the previously proposed mechanism of the ferroelectricity.

Oral presentation

Measurement of contamination distribution for operating floor of the Fukushima Daiichi Unit 2 reactor building by $$gamma$$ camera, 2; Performance verification of the $$gamma$$ camera by pre-test

Okada, Takashi; Kanayama, Fumihiko; Fukushima, Mineo; Yoshimoto, Katsunobu; Hanyu, Toshinori; Kawanobe, Takayuki; Takahashi, Yoshiaki*; Oikawa, Kageharu*; Matsumoto, Yasuhiro*; Kishi, Kazuyoshi*; et al.

no journal, , 

In order to measure contamination distribution for operating floor of the Fukushima Daiichi Unit 2 reactor building by the $$gamma$$ camera which JAEA developed, the trial examination which determines a measurement condition was done.

Oral presentation

Measurement of contamination distribution for operating floor of the Fukushima Daiichi Unit 2 reactor building by $$gamma$$ camera, 3; Measurement and analysis

Fukushima, Mineo; Okada, Takashi; Kanayama, Fumihiko; Yoshimoto, Katsunobu; Hanyu, Toshinori; Kawanobe, Takayuki; Takahashi, Yoshiaki*; Oikawa, Kageharu*; Matsumoto, Yasuhiro*; Kishi, Kazuyoshi*; et al.

no journal, , 

Contamination distribution for operating floor of the Fukushima Daiichi Nuclear Power Plant was measured from opened blow out panel using $$gamma$$ viewer "$$gamma$$-eyeII" developed by JAEA. It is obtained that one of the main contaminated area is on the reactor well and contamination level of the surface of west side floor is lower than lower limit level of detector.

Oral presentation

Electronic structure observation of BaTiO$$_{3}$$ using resonant X-ray emission at Ba L$$_{3}$$ and Ti K edges

Yoshii, Kenji; Yoneda, Yasuhiro; Jarrige, I.*; Fukuda, Tatsuo; Nishihata, Yasuo; Suzuki, Chikashi; Ito, Yoshiaki*; Yoshikado, Shinzo*; Fukushima, Sei*

no journal, , 

We have studied the electronic properties of the ferroelectric barium titanate BaTiO$$_{3}$$ using resonant X-ray emission spectroscopy (RXES) and X-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS) at the Ba L$$_{3}$$ and Ti K absorption edges. Contrary to a previous study, we found no fine structure in the pre-edge area of the PFY-XAS spectrum at the Ba L3 edge, and no temperature-induced spectral change was observed across the Curie temperature (130$$^{circ}$$C). This result is not supportive of the possible presence of the displacement around Ba$$^{2+}$$ at the Curie temperature. RXES spectra were measured at the Ti K edge. The photon energy of the emission peak is found to be nearly constant throughout the absorption edge for all three compounds. We deduce the Ti 3d states to have a delocalized character, in contrast with the Ba 5d states, a property which is consistent with the proposed scenario of the formation of electric dipoles in BaTiO$$_{3}$$.

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