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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:0.00(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)LaTa
O
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)LaNb
O
and (CuCl)LaTa
O
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)LaNb
O
well reproduces that observed at a triple-axis spectrometer, exhibiting characteristics of spin-singlet dimers. On the other hand, (CuCl)LaTa
O
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:28 Percentile:62.06(Chemistry, Physical)Topotactic reaction of the Ruddlesden-Popper phase SrFe
O
(
0.18) with polytetrafluoroethylene yields a highly fluorinated phase Sr
Fe
O
F
(x
0.44), compared with Sr
Fe
O
F
prepared by the reaction of Sr
Fe
O
and F
gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and
Fe M
ssbauer 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:65.58(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:26 Percentile:48.29(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.
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 SrFe
O
with the Teflon polymer yields a highly fluorinated phase Sr
Fe
O
O
(x
0.44). The crystal/magnetic structures and anion composition are determined by a combination of neutron diffraction and
Fe M
ssbauer 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.
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
Tomiyasu, Keisuke*; Kageyama, Hiroshi*; Tsujimoto, Yoshihiro*; Yoshimura, Kazuyoshi*; Taylor, J. W.*; Llobet, A.*; Kakurai, Kazuhisa; Yamada, Kazuyoshi*
no journal, ,
no abstracts in English
Mizumaki, Masaichiro*; Taguchi, Munetaka*; Agui, Akane; Kawamura, Naomi*; Tassel, C.*; Tsujimoto, Yoshihiro*; Kageyama, Hiroshi*
no journal, ,
no abstracts in English