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Kambe, Takashi*; Komatsu, Takuma*; Michiuchi, Takamasa*; Hayakawa, Hiroki*; Oishi, Daisuke*; Hanasaki, Noriaki*; Yoshii, Kenji; Ikeda, Naoshi*
Journal of Physics; Conference Series, 200, p.012077_1 - 012077_4, 2010/02
Times Cited Count:4 Percentile:79.48(Materials Science, Multidisciplinary)A magneto-electric effect (ME) was observed in a charge-ordered ferroelectric LuFeO
. The dielectric response in a three-dimensional charge-ordered phase is strongly influenced by magnetic field, especially around the ferri-magnetic ordering temperature. We also show the relation between the oxygen stoichiometry and the ME signal character above the magnetic transition temperature.
Michiuchi, Takamasa*; Yokota, Yusuke*; Komatsu, Takuma*; Hayakawa, Hironori*; Kuroda, Tomoko*; Maeda, Daisuke*; Matsuo, Yoji*; Mori, Shigeo*; Yoshii, Kenji; Hanasaki, Noriaki*; et al.
Ferroelectrics, 378(1), p.175 - 180, 2009/00
Times Cited Count:18 Percentile:58.51(Materials Science, Multidisciplinary)We have synthesized the samples of LuFeO
, which shows the ferroelectricity due to charge ordering of Fe ions, under several different reducing conditions using a CO
-CO flow. The reducing condition was changed by changing a flow ratio of CO
and CO. It was found that the flow ratio of CO
/CO of about 5 provided the sample with the highest magnetic transition temperature of 240-250 K. This sample showed the dielectric constant of 10000 at room temperature. The imaginary part of the dielectric response offered the activation energy of 0.4-0.5 eV, which is slightly larger than that reported previously (about 0.3 eV). We will perform further investigation of the physical properties of this sample to clarify full details and their origin of LuFe
O
.
Yoshii, Kenji; Yoneda, Yasuhiro; Maeda, Daisuke*; Yokota, Yusuke*; Michiuchi, Takamasa*; Komatsu, Takuma*; Ikeda, Naoshi*; Matsuo, Yoji*; Mori, Shigeo*
Japanese Journal of Applied Physics, 47(9), p.7599 - 7602, 2008/09
Times Cited Count:8 Percentile:32.75(Physics, Applied)We have investigated the physical properties of HoFeO
and R
R'
Fe
O
(R, R': rare earths). Dielectric measurements showed their dielectric constants of 1000 at around room temperature, which is characteristic of the RFe
O
series (R: rare earths). However, the magnetic transition temperatures and the coherency in dielectric response were found to be different from those of RFe
O
reported so far. Interestingly, these materials suggested higher ferroelectric temperatures than those reported so far, suggesting a possibility of application of these materials.
Komatsu, Takuma*; Kambe, Takashi*; Michiuchi, Takamasa*; Hayakawa, Hironori*; Oishi, Daisuke*; Hanasaki, Noriaki*; Ikeda, Naoshi*; Yoshii, Kenji
no journal, ,
LuFeO
is a ferroelectric material arising from the real-space ordering of Fe charges below 330 K. In this paper, we measured the magnetic-field dependence of dielectric response in this material. We report a change of dielectric constant depending on the measurement temperature and applied magnetic field.
Ikeda, Naoshi*; Kambe, Takashi*; Komatsu, Takuma*; Michiuchi, Takamasa*; Hayakawa, Hironori*; Hanasaki, Noriaki*; Yoshii, Kenji; Matsuo, Yoji*; Mori, Shigeo*
no journal, ,
A review will be given on the new type of ferroelectric material LuFeO
. This oxide becomes ferroelectric below about 330 K, owing to the charge-ordered arrangement of Fe ions on a triangular lattice: This is a novel mechanism of ferroelectricity. We discuss the experimental results obtained from resonant X-ray diffraction, dielectric response, polarization and magnetization to show some interesting properties of this new ferroelectric oxide.
Katori, Takuma*; Kobayashi, Kenta*; Yasue, Kenichi; Niwa, Masakazu; Komatsu, Tetsuya; Hosoya, Takashi*; Sasao, Eiji
no journal, ,
Understanding fault zone evolution is important for constructing the topographical and geological model for a time scale more than one million year. We analyzed fault rocks of the Byobuyama fault in Tono area by several methods including structural analysis in the field and using optical microscope, determination of mineral composition based on X-ray diffraction analysis, and chemical composition analysis using an X-ray fluorescence instrument. Based on these analyses, studied fault rocks could record several stages of fault activity under different depths and stress regimes.
Katori, Takuma*; Kobayashi, Kenta*; Niwa, Masakazu; Shimizu, Mayuko; Komatsu, Tetsuya; Yasue, Kenichi; Horiuchi, Yasuharu
no journal, ,
We performed structural analyses and XRD, XGT and EPMA analyses of fault rocks of the Byobuyama fault to reconstruct the history of the fault activity at shallow depth, as a case study for improving research technique to reveal the history of active faults. The results show that fault gouge zone along the fault has experienced activities of several stages under different stress, and significant differences in the deformation and alteration mechanism exist between these stages. Especially, the flow deformation of the fault gouge indicates that a large amount of fluid was present during the deformation. Abundance of illite infers that such fault gouge was formed by relatively high temperature fluid. In addition, eluviation structure of albite may indicate a deformation under environment such as to promote reaction solution. In this presentation, we discuss the vicissitudes of deformation and alteration mechanism in the fault gouge along the Byobuyama fault.