| Project/Area Number |
60580045
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
ITOH Kazuyuki Hiroshima Univ., Associate Professor, 理学部, 助教授 (40033914)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Structural Phase Transition / Crystal Structure Analysis / 強誘電体 |
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| Research Abstract |
The structural phase transition is characterized by the atomic displacement or the orientational change of the atomic group. Therefore, it is important to investigate the crystal structure above and below the transition point. Along this line, we studied the structural change of following compounds.
1) At first, we made a cryostat, which was set on a four-circle diffractometer, in order to measure Bragg reflections at high temperatures.
2) It is concluded that the magnitude of the electric dipole moment of triglycine sulfate crystals depends on the temperature. This result requires to consider this newly found nature to construct the real picture of the structural phase transitition.
3) SrTi <O_3> was investigated by determining the coefficients of the atomic potential function. It turns out that the quadratic term becomes small with approaching the transition temperature leading to the understanding of lattice instability from the structural viewpoint. The calculation was carried out by a personal computer which was taken by the grant-in-aid.
4) Following investigations are now in progress; i.e. the study of the melting mechanism of <LiH_3> <(SeO_3)_2> , the study of the disordered structure of DLP crystals and the study of the transition mechanism of the hydrogen bonded crystals <KH_2> <PO_4> , ( <NH_4> ) <H_2> <PO_4> and <KH_3> <(SeO_3)> <_2> .
We will contribute to get deeper understanding of the mechanism of the structural phase transition by completing a series of these studies.
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