Manipulation of vortex states in small superconducting thin films

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K05537
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: The University of Electro-Communications
• Principal Investigator: KOKUBO NOBUHITO 電気通信大学, 大学院情報理工学研究科, 准教授 (80372340)
• Co-Investigator(Kenkyū-buntansha): 岡安 悟 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 先端基礎研究センター, 研究主幹 (50354824)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 超伝導材料・素子 / 量子渦 / メゾスコピック系 / 走査プローブ顕微鏡 / 低温物性

Outline of Final Research Achievements

The manipulation of quantum vortex states was made by strategically introducing holes in small dots of superconducting thin films. Using a scanning SQUID microscope we were able to image symmetric cluster made of an antivortex and three vortices in a superconducting triangle dot by utilizing the magnetic history and the pinning effect. We found that the observed vortex cluster is metastable state, realized through the non-equilibrium process and is not induced when the sample is cooled in a uniform magnetic field.
We also found that the penetration of vortices in small superconducting dots is highly size dependent and obey a universal scaling relationship. The results are useful for trapping or eliminating vortices in superconducting nano-micro structures, which can be crucial elements for designing various devices for quantum information processing, memory and metrology.

Free Research Field

低温物理

Academic Significance and Societal Importance of the Research Achievements

磁場中の微小超伝導体が示す物理現象の基礎的な理解につながるだけではなく、近年急速に発展する量子情報技術、とりわけ超伝導ナノ・マイクロ構造体を用いた様々な応用デバイスの性能向上に必要な基礎資料となる。