Vortex matter confined in mesoscopic superconductors of different geometric shapes

2014 Fiscal Year Final Research Report

• Project/Area Number: 23540416
• 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, 情報理工学(系)研究科, 准教授 (80372340)
• Co-Investigator(Kenkyū-buntansha): OKAYASU Satoru 日本原子力研究開発機構, 先端基礎研究センター, 研究主幹 (50354824)
• Project Period (FY): 2011-04-28 – 2015-03-31
• 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（SSM） / 低温物性

Outline of Final Research Achievements

We present direct observation of multi-vortex states confined in square and triangle dots of amorphous superconducting films by a scanning SQUID microscope. The results allow us not only to find unique vortex states imposed by the sample shape, but also to trace systematically, for the first time, how the vortex pattern evolves with an applied magnetic field. Although the symmetry induced-anti-vortex state has not yet been found, as related to this issue, we obtain several novel findings of (1) the filling rule for square vortex shells, (2) bistability of vortex states, and (3) configurational symmetry and stability with respect to the geometrical deformation. These features are governed by the commensurability between the geometry and the vortex arrangement in dots.

Free Research Field

数物系科学