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Kawamura, Seiko; Nakajima, Kenji; Inamura, Yasuhiro; Tsujimoto, Yoshihiro*; Kitada, Atsushi*; Takeiri, Fumitaka*; Kageyama, Hiroshi*; Ajiro, Yoshitami*; Nishi, Masakazu*; Kakurai, Kazuhisa
Journal of Physics; Conference Series, 320, p.012037_1 - 012037_5, 2011/09
Times Cited Count:0 Percentile:0.03(Physics, Condensed Matter)The magnetic ground state of (CuCl)LaNbO has been suggested to be a spin-singlet state with an excitation gap of meV, while (CuCl)LaTaO has an antiferromagnetic (AFM) ground state. The systems are suspected to be a frustrated quantum spin system due to the competition between the nearest and next-nearest exchange interactions. We have studied magnetic excitation in these systems by ToF inelastic neutron scattering technique. The measurements were performed on powder samples of (CuCl)LaNbO and (CuCl)LaTaO at a disk-chopper-type spectrometer AMATERAS in J-PARC. In both systems, a band-like excitation was observed at meV. The dependence of the intensity of magnetic excitation around 2 meV for (CuCl)LaNbO well reproduces that observed at a triple-axis spectrometer, exhibiting characteristics of spin-singlet dimers. On the other hand, (CuCl)LaTaO in the AFM state exhibits a different dependence.
Tsujimoto, Yoshihiro*; Yamaura, Kazunari*; Hayashi, Naoaki*; Kodama, Katsuaki; Igawa, Naoki; Matsushita, Yoshitaka*; Katsuya, Yoshio*; Shirako, Yuichi*; Akaogi, Masaki*; Muromachi, Eiji*
Chemistry of Materials, 23(16), p.3652 - 3658, 2011/08
Times Cited Count:27 Percentile:61.99(Chemistry, Physical)Topotactic reaction of the Ruddlesden-Popper phase SrFeO ( 0.18) with polytetrafluoroethylene yields a highly fluorinated phase SrFeOF (x 0.44), compared with SrFeOF prepared by the reaction of SrFeO and F gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and Fe Mssbauer spectroscopy measurements demonstrate that the new oxyfluoride perovskite has no anion deficiencies and adopts the tetragonal structure (space group 4/) with lattice constants = 3.87264(6) and = 21.3465(6) at room temperature. The fluoride ions preferentially occupy the terminal apical anion sites with oxide ions in a disordered manner, which results in square pyramidal coordination around iron.
Tomiyasu, Keisuke*; Kageyama, Hiroshi*; Lee, C.*; Whangbo, M. H.*; Tsujimoto, Yoshihiro*; Yoshimura, Kazuyoshi*; Taylor, J. W.*; Llobet, A.*; Trouw, F.*; Kakurai, Kazuhisa; et al.
Journal of the Physical Society of Japan, 79(3), p.034707_1 - 034707_4, 2010/03
Times Cited Count:16 Percentile:66.10(Physics, Multidisciplinary)Takeyasu, Masanori; Iida, Takao*; Tsujimoto, Tadashi*; Yamasaki, Keizo*; Ogawa, Yoshihiro*
Journal of Environmental Radioactivity, 88(1), p.74 - 89, 2006/00
Times Cited Count:25 Percentile:48.96(Environmental Sciences)The concentrations of Pb and Bi in rainwater was measured by a low background Ge detector. The concentrations of Pb and Bi were inverse relations with rainfall rate in some rainfall events, and the concentration ratio of Bi to Pb would be a weak inverse relation with rainfall rate. The model was considered about the scavenging effects of rainfall to Radon decay products, and those results were discussed with the model.
Mizumaki, Masaichiro*; Taguchi, Munetaka*; Agui, Akane; Kawamura, Naomi*; Tassel, C.*; Tsujimoto, Yoshihiro*; Kageyama, Hiroshi*
no journal, ,
no abstracts in English
Tsujimoto, Yoshihiro*; Yamaura, Kazunari*; Matsushita, Yoshitaka*; Muromachi, Eiji*; Hayashi, Naoaki*; Kodama, Katsuaki; Igawa, Naoki; Shirako, Yuichi*; Akaogi, Masaki*
no journal, ,
Topotactic reaction of the n = 2 Ruddlesden-Popper phase SrFeO with the Teflon polymer yields a highly fluorinated phase SrFeOO (x 0.44). The crystal/magnetic structures and anion composition are determined by a combination of neutron diffraction and Fe Mssbauer spectroscopy experiments. Fluoride anions selectively occupy the terminal apical anion sites, leading to the square pyramidal coordination around the Fe metal center. The oxyfluoride material adopts a simple antiferromagnetic ordered structure with k = (1/2 1/2 0) below 390 K.
Tomiyasu, Keisuke*; Kageyama, Hiroshi*; Tsujimoto, Yoshihiro*; Yoshimura, Kazuyoshi*; Taylor, J. W.*; Llobet, A.*; Kakurai, Kazuhisa; Yamada, Kazuyoshi*
no journal, ,
no abstracts in English
Kawamura, Seiko; Nakajima, Kenji; Inamura, Yasuhiro; Tsujimoto, Yoshihiro*; Kitada, Atsushi*; Takeiri, Fumitaka*; Kageyama, Hiroshi*; Ajiro, Yoshitami*; Nishi, Masakazu*; Kakurai, Kazuhisa
no journal, ,
no abstracts in English