Enhancement of critical current density for high-Tc superconductors by hybrid pinning in all magnetic field orientations

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06269
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Kumamoto University
• Principal Investigator: Sueyoshi Tetsuro 熊本大学, 大学院先端科学研究部(工), 助教 (20315287)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 高温超伝導体 / 臨界電流密度 / 磁束ピンニング / 照射欠陥 / 異方性

Outline of Final Research Achievements

Flux pinning properties of columnar defects (CDs) were investigated at the magnetic field B parallel to the ab-plane (B || ab) in high-Tc superconductors, where CDs tilted off the ab-plane were systematically produced by heavy-ion irradiations. The critical current density Jc at B || ab drastically increases when CDs were installed at crossing angles of +-5 deg. relative to the ab-plane. By contrast, CDs tilted even at 5 deg. relative to the ab-plane have no contribution to flux pinning at B || ab, whereas the strong pinning is exhibited at the magnetic field along their length. This study is the first to experimentally clarify the splay effect of CDs at B || ab, leading to the guideline for strong and isotropic pinning landscape in high-Tc superconducting materials.

Free Research Field

電子物性工学

Academic Significance and Societal Importance of the Research Achievements

本研究では，重イオン照射を用いて系統的に角度を制御した柱状欠陥を導入することで，高温超伝導体のab面方向の磁場での柱状欠陥のピン止め効果を初めて実験的に明らかにし，ab面方向の量子化磁束特有のピン止め物理に対する知見を得た．また，高温超伝導体のab面方向の磁場での高臨界電流密度化（高Jc化）に対して，有効となる柱状欠陥の導入形態を明らかにしたことで，実用化の妨げとなっているJcの異方性の緩和のための指針の一つとなり得る．