| Project/Area Number |
17K05810
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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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| Research Field |
Inorganic chemistry
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| Research Institution | Osaka University |
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Principal Investigator |
NAKAMOATO Yuki 大阪大学, 基礎工学研究科, 特任准教授(常勤) (90379313)
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| Project Period (FY) |
2017-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2018: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2017: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
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| Keywords | 高圧力 / 超伝導 / 構造相転移 / アルカリ土類金 / アルカリ土類金属 / 高圧 / X線回折 / 超高圧力 / 低温 / DFT計算 |
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| Outline of Final Research Achievements |
The purpose of this study was to clarify the relationship between the superconducting transition temperature (Tc) and the crystal structure of alkaline earth metals, which have a high superconducting transition temperature among the elements. A detailed temperature-pressure phase diagram was created focusing on strontium (Sr). The existence of a new high pressure phase (Sr-VI) having higher Tc than previously reported in Sr was found. This high pressure phase (Sr-VI) appears by applying pressure only at low temperature below 100K. In addition, the existence of a new crystalline phase (Sr-VII) with hcp structure as the higher pressure phase than that of the Sr-VI phase and the stable region were clarified. The above results suggest the existence of a low-temperature and high-pressure phase with a higher Tc for calcium, which has the highest superconducting transition temperature of the elements.
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| Academic Significance and Societal Importance of the Research Achievements |
元素の中でも超伝導転移温度が圧力によって上昇するものは稀であり、その中で最も高い超伝導転移温度を示すカルシウムと同族であるストロンチウム、バリウムについて精密に結晶構造を調べることで、アルカリ土類金属についてのシークエンスを得ることができる。
ストロンチウムについて高い超伝導転移温度を示す相の精密結晶構造解析を行い、結晶構造と超伝導性の関係を明らかにしたことは高温超伝導の発現機構の解明の一助となる。さらに理論的に超伝導性発現機構が解明されれば、超伝導転移温度の改善、さらには室温超伝導体など新規高温超伝導物質の材料設計につながる。
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