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O
(
= Nb, Ta)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：0.03The magnetic ground state of (CuCl)LaNb
O 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.
AgIn
Li, D. X.*; Yamamura, Tomoo*; Yubuta, Kunio*; Nimori, Shigeki*; Haga, Yoshinori; Shikama, Tatsuo*
Journal of Physics; Conference Series, 320, p.012041_1 - 012041_6, 2011/09
Times Cited Count：7 Percentile：86.05
O
Matsumoto, Keisuke*; Koyama, Tsukasa*; Mori, Shigeo*; Yoshii, Kenji; Ikeda, Naoshi*
Journal of Physics; Conference Series, 320, p.012085_1 - 012085_5, 2011/09
Times Cited Count：0 Percentile：0.03In order to clarify the stability of charge ordered structure (CO) in charge- and spinfrustrated ferrite YbFeO, we have investigated changes of the CO structure by partial substitution of Mn
for Fe in YbFeO by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that subtle substitution of Mn for Fe in YbFeO destroyed drastically the CO structure with the wave vector of q=
1/3 1/3 1/2
and, instead, induced polar clustering structure characterized by honeycomb shaped diffuse scatterings in the reciprocal space. The formation of polar clustering structure should be responsible for the characteristic dielectric dispersion.
Torigoe, Shuhei*; Ishimoto, Yutaro*; Hanasaki, Noriaki*; Nogami, Yoshio*; Matsumura, Daiju; Yoshii, Kenji; Yoneda, Yasuhiro; Nishihata, Yasuo
Journal of Physics; Conference Series, 320, p.012078_1 - 012078_4, 2011/09
Times Cited Count：1 Percentile：36The X-ray absorption spectra of some pyrochlore niobates reveal the valence of the Nb ion in each material, and the displacement of the Nb ions from the center of the oxygen octahedra in the pyrochlore niobates YCaNbO
and NdCaNbO, which is consistent with the previous report of the neutron diffraction.
Wakimoto, Shuichi
no journal, ,
no abstracts in English
