| Project/Area Number |
18K04694
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26020:Inorganic materials and properties-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
Kawaji Hitoshi 東京工業大学, 科学技術創成研究院, 教授 (10214644)
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| Project Period (FY) |
2018-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 構造相転移 / 巨大粒度効果 / 強誘電体 / 強弾性ドメイン構造 / トリジマイト型構造 / 強誘電体結晶 / 強弾性ドメイン / 相転移 / ドメイン構造 |
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| Outline of Final Research Achievements |
Although structural phase transitions in solids are caused by subtle changes in the arrangement of atoms constituting the crystal, a “giant grain size effect” has been observed in some ferroelectric crystals, in which phase transitions appear and disappear at a macroscopic size of 1 mm, which is beyond the range of ordinary observation. We synthesized single crystal samples of CsZnPO4, CsCoPO4, RbZnPO4, and RbCoPO4 with high chemical purity and physical purity, such as defects, and investigated their thermophysical properties. The results revealed that the generation of ferroelastic domain structures associated with ferroelastic phase transitions at higher temperatures has a significant effect on the giant grain size effect.
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| Academic Significance and Societal Importance of the Research Achievements |
潜熱を伴う一次相転移において、核生成や核成長が重要な役割を示すことはすでに知られていたが、固相間相転移において結晶ドメイン壁が核生成サイトとなることはあまり知られていなかった。結晶ドメイン壁は結晶内部とは異なる対称性を持ち、その対称性の違いにより相転移の引き金になることを発見したことは大きな学術的意義を持っている。
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