2022 Fiscal Year Final Research Report
Study of Unconventional Multiple-Superconductivity and Non-Fermi-Liquid State in Uranium Compounds
| Project/Area Number |
20K03851
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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 13030:Magnetism, superconductivity and strongly correlated systems-related
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| Research Institution | Tohoku University |
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Principal Investigator |
SHIMIZU YUSEI 東北大学, 金属材料研究所, 助教 (90751115)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 強相関電子系 / ウラン化合物 / スピン三重項超伝導 / アクチナイド物性 / 磁気特性 / 非フェルミ液体異常金属 / 電子状態 / 新奇相 |
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| Outline of Final Research Achievements |
The purpose of this study was to elucidate superconducting and magnetic properties of unconventional superconductors and to explore novel quantum phases in 5f-electron systems. We have developed ultra-high-precision magnetization transducers, which had enabled quantitative dc magnetization measurements for tiny UNi2Al3 single crystals. Our data clarified the nature of Pauli-paramagnetic effects in UNi2Al3. In addition, magnetization and specific-heat measurements for novel spin-triplet superconductor UTe2 have been performed to clarify its superconducting quasiparticle excitations and magnetic properties. Moreover, precise magnetization and specific heat measurements for UBe13 have been carried out, and we have observed an anisotropic magnetic anomaly owing to an unusual 5f-electronic state. We also explored novel uranium-based materials, and succeeded in growing high-quality single crystalline URhSn, and found a nontrivial quantum phase enhanced by magnetic fields.
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| Free Research Field |
強相関電子系超伝導
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| Academic Significance and Societal Importance of the Research Achievements |
ウラン化合物の異常な超伝導特性・磁気特性の解明は、未解明現象の多いスピン三重項超伝導に関する基礎学理を構築することに繋がる。スピン三重項超伝導は量子技術への応用が期待されているが、固体には珍しくその有力候補はウラン系化合物に限られているため、ウラン系超伝導に関する研究成果は希少価値が高い。また、本研究によって開発した超高精度磁化測定技術は、様々な強相関物質の極低温温度領域における磁気特性を明らかにする上で非常に有効であり、今後幅広い応用が期待される。さらにURhSnの新奇量子相の発見は、「隠れた秩序相」などの5f電子系異常物性を理解する重要なステップとなる成果である。
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