| Project/Area Number |
18K04940
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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 29020:Thin film/surface and interfacial physical properties-related
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| Research Institution | Okayama University |
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Principal Investigator |
Eguchi Ritsuko 岡山大学, 異分野基礎科学研究所, 助教 (50415098)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 超伝導 / 酸化物界面 / 強誘電性 / 酸化物薄膜界面 / 強誘電特性 |
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| Outline of Final Research Achievements |
In order to introduce ferroelectric fluctuations into the superconducting properties at the LaAlO3/SrTiO3 interface, LaAlO3/CaxSr1-xTiO3 was fabricated, in which the substrate was replaced SrTiO3 known as a quantum paraelectric material with CaxSr1-xTiO3 showing a ferroelectric phase transition. The anomalies associated with the ferroelectric phase transition were observed in the temperature dependence of resistivity at the normal state, and then the superconducting transition was observed at a lower temperature. The maximum value of the superconducting transition temperature (Tc) was slightly higher than that of the LaAlO3/SrTiO3 interface system. It was clarified that the phase diagram of Tc with respect to the conductivity in the normal state was different from that of the LaAlO3/SrTiO3 interface system.
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| Academic Significance and Societal Importance of the Research Achievements |
酸素欠損を持つバルクのCaxSr1-xTiO3-dは強誘電相転移を示しさらに低温では超伝導を示すことが報告された。この報告により強誘電性揺らぎの超伝導への影響が議論され、強誘電性揺らぎがTcの上昇に効果的に働くのではないかという予想が理論的になされた。このようなシナリオは、銅酸化物や鉄系の高温超伝導体において、超伝導が反強磁性相近傍に出現するということに類似している。このように様々な電子物性相において、一見悪影響を及ぼすと予想される電子物性相の相境界近傍で新奇な物性や機能が現れるということは物性研究において大変興味深いポイントであり、新たな機能を創出するプラットフォームとなり得ると期待される。
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