2023 Fiscal Year Final Research Report

Elucidation of factors controlling critical current density of high-Tc cuprates with a focus on the electronic phase diagram

Research Project

PDF

Project/Area Number	21H01377
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 21050:Electric and electronic materials-related
Research Institution	National Institute of Advanced Industrial Science and Technology
Principal Investigator	Ishida Shigeyuki 国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 主任研究員 (90738064)
Co-Investigator(Kenkyū-buntansha)	永崎洋国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 首席研究員 (20242018) 辻本学国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 主任研究員 (20725890) 西尾太一郎東京理科大学, 理学部第二部物理学科, 教授 (40370449) 柏木隆成筑波大学, 数理物質系, 講師 (40381644)
Project Period (FY)	2021-04-01 – 2024-03-31
Keywords	臨界電流密度 / 磁束ピン止め / 超伝導臨界温度 / 上部臨界磁場 / 超流動密度 / 銅酸化物高温超伝導体 / 電子相図
Outline of Final Research Achievements	Using single crystals of high-Tc cuprates, we clarified how the critical current density (the maximum current density up to that zero electrical resistance can maintain) changes with carrier doping levels and chemical composition. We discovered an unusual behavior of the critical current density, previously unknown, which shows a peak in the underdoped region. We investigated the doping dependence of the superconducting parameters related to critical current density, namely the upper critical field (the maximum magnetic field up to that superconducting state can maintain) and the superfluid density (the density of Cooper pairs responsible for superconductivity). These parameters increased monotonically with doping levels and showed no correlation with the behavior of critical current density in the underdoped region. This result suggests a novel flux pinning mechanism that had previously been overlooked.
Free Research Field	超伝導
Academic Significance and Societal Importance of the Research Achievements	液体窒素温度以上でもゼロ抵抗状態を維持できる銅酸化物高温超伝導体の超伝導機構解明および応用展開は長年の課題である。臨界電流密度は応用上極めて重要なパラメータであり、その顕著な増大をもたらす未解明の決定因子を発見したことの意義は大きい。今後、臨界電流密度の増大機構の解明することで、基礎的な知見の蓄積と超伝導応用の加速につながると期待される。