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P
O
Hase, Masashi*; D
nni, A.*; Ozawa, Kiyoshi*; Kitazawa, Hideaki*; Sakai, Osamu*; Pomjakushin, V. Y.*; Keller, L.*; Kaneko, Koji; Metoki, Naoto; Kakurai, Kazuhisa; et al.
Journal of Physics; Conference Series, 340, p.012066_1 - 012066_7, 2012/00
Times Cited Count：1 Percentile：44.95(Physics, Condensed Matter)We determined the magnetic structure below 
K of the spin-5/2 antiferromagnetic (AF) trimer substance SrMnPO using neutron powder diffraction experiments. The incommensurate propagation vector is expressed as [0, 
, 0], due to competition between the nearest-neighbor and next-nearest-neighbor interactions in trimerized chains. The value of is 0.316 to 0.331, changing rapidly at 
K. We confirmed that the intra-trimer 
interaction is AF. The magnetic excitation peaks were obsereved at 0.46, 0.68, and 1.02 meV. The weak Q dependence indicates the discrete energy levels, which do not contradict the AF trimer model with the intra-trimer interaction value of 0.29 meV (3.4 K).
POHase, Masashi*; Matsuda, Masaaki*; Kaneko, Koji; Metoki, Naoto; Kakurai, Kazuhisa; Yang, T.*; Cong, R.*; Lin, J.*; Ozawa, Kiyoshi*; Kitazawa, Hideaki*
Physical Review B, 84(21), p.214402_1 - 214402_6, 2011/12
Times Cited Count：10 Percentile：42.01(Materials Science, Multidisciplinary)
-AgCuPO
Hase, Masashi*; Matsuda, Masaaki; Kakurai, Kazuhisa; Ozawa, Kiyoshi*; Kitazawa, Hideaki*; Tsujii, Naohito*; Dnni, A.*; Kuroe, Haruhiko*
Physical Review B, 76(13), p.134403_1 - 34403_5, 2007/10
Times Cited Count：2 Percentile：12.52(Materials Science, Multidisciplinary)The magnetism of -AgCuPO has been studied using inelastic neutron scattering and magnetic susceptibility measurements on powder sample. A well-defined symmetric broad inelastic peak was observed at 6.2meV energy transfer, indicating the existence of spin-gap excitation. From the Q-dependence of the inelastic magnetic intensities it is concluded that the strongest exchange interaction exists in the Cu-O-P-O-Cu path and that the antiferromagnetic alternating chain model with two exchange interactions values of 80 and 14K can quantitatively explain the experimental results.
(P
O
OD) by inelastic neutron scattering measurementsHase, Masashi*; Matsuda, Masaaki; Kakurai, Kazuhisa; Ozawa, Kiyoshi*; Kitazawa, Hideaki*; Tsujii, Naohito*; Dnni, A.*; Kono, Masanori*; Hu, X.*
Physical Review B, 76(6), p.064431_1 - 064431_5, 2007/08
Times Cited Count：28 Percentile：71.35(Materials Science, Multidisciplinary)The magnetism of spin-1/2 trimer chain system Cu(POOD) is studied by means of inelastic neutron scattering. A spin excitation gap of 9.8meV corresponding to singlet -triplet excitation is observed and together with the magnetization plateau data the AF exchange interaction parameters of the trimer system could be determined as J
=111K and J=30K.
Kakurai, Kazuhisa; Matsuda, Masaaki; Hase, Masashi*; Ozawa, Kiyoshi*; Kitazawa, Hideaki*; Tsujii, Naoto*; Doenni, A.*; Hu, X.*; Kuroe, Haruhiko*
no journal, ,
We report powder sample inelastic neutron scattering experiments on spin gap systems. Recently the magnetization plateau phenomenon in quantum spin systems are drawing attention of both theoretical and experimental physicists. Although the relevant exchange energies can be estimated from the magnetic susceptibility measurements assuming some theoretical models, we can only speculate the exchange interaction scheme causing the singlet ground state based on the structural and bonding information. We shall present examples of powder sample inelastic neutron scattering studies on the antiferromagnetic alternating chain system -AgCuPO and trimer chain compound Cu(POOD) using triple axis spectrometer at the steady state neutron source and stress that this kind of research on novel quantum systems could be very effectively performed using the low-energy chopper type spectrometer being built for the J-PARC spallation neutron source.
Motoyama, Aoi*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Hase, Hideaki*; Koyama, Takao*; Sakanaka, Shinya*; Yamaya, Yusuke*; Aizawa, Koki*; et al.
no journal, ,
no abstracts in English
Motoyama, Aoi*; Ichiki, Masahiro*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Koyama, Takao*; Sakanaka, Shinya*; Hase, Hideaki*; Aizawa, Koki*; et al.
no journal, ,
We compiled the magnetotelluric (MT) and geomagnetic transfer function (GDS) data which were acquired by Uchida (2004), Umeda et al. (2008), Asamori et al. (2011), Uyeshima (private comm.) and Ogawa (private comm). The 118 observation sites locate in the study area. Both MT and GDS frequency response was used to model three-dimensional resistivity distribution of the southern Tohoku district, NE Japan. The resultant resistivity model reveals no conductor beneath the onshore forearc in Fukushima prefecture. The model rather shows resistor there with over several-thousand ohm-m, which corresponds to the Abukuma batholiths. Thus, our model indicates that the area only around Iwaki-city is peculiar forearc, where fluid migrates upward from deep crust.
Usui, Yoshiya*; Ueshima, Makoto*; Hase, Hideaki*; Ichihara, Hiroshi*; Aizawa, Koki*; Koyama, Takao*; Sakanaka, Shinya*; Ogawa, Tsutomu*; Yamaya, Yusuke*; Nishitani, Tadashi*; et al.
no journal, ,
In the back-arc area of the southern Tohoku region, there are several quaternary volcanos and active faults that have the potential to cause M7-class inland earthquakes. In the vicinity of some of the volcanoes, deep low-frequency earthquakes occur, implying the transfer of melt or aqueous fluid. So as to reveal the magma supply system around the area, it is important to reveal the distribution of the subsurface fluid. Also, understanding the fluid distribution helps elucidate the earthquake generation process. To delineate the subsurface electrical resistivity structure, the authors estimated the resistivity structure in the area by performing magnetotelluric surveys and generating the 3-D resistivity structure model with high resolution. In this study, the authors show the resultant electrical resistivity structure and discuss the subsurface fluid distribution as well as its relationship with the volcanic and seismic activities around the study area.
