Real time observation of vortex dynamics using microwave microscope

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K20891
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Maeda Atsutaka 東京大学, 大学院総合文化研究科, 教授 (70183605)
• Co-Investigator(Kenkyū-buntansha): 加藤 雄介 東京大学, 大学院総合文化研究科, 教授 (20261547)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: マイクロ波顕微鏡 / フラックスフロー / ホール効果 / 鉄カルコゲナイド / BdG方程式 / 銅酸化物高温超伝導体

Outline of Final Research Achievements

This project aims to clarify the complicated mechanism of the energy dissipation by the driven vortices of superconductors. Because of the Covid-19 issue and the shortage of liquid He caused by the Russian invasion, we have not yet achieved the initial purpose. The achievements are as follows. (1) We have fabricated the AFM-type scanning microwave microscope which works at liquid helium temperature. (2) Using time dependent GL equation, we obtained the driving force acting on a moving vortex and clarified its origin. (3) We developed the microwave Hall effect measurement system for highly conductive materials and investigated the microwave flux-flow Hall effect of high-Tc cuprates and FeSe, all of which are expected to have quantum clean vortex cores. In cuprates, we observed large Hall angles as is theoretically expected. On the other hand, in FeSe, the Hall angle is small because of the cancelation by two different bands. This is a novel phenomenon of a multiband superconductor.

Free Research Field

固体物理学

Academic Significance and Societal Importance of the Research Achievements

本研究は，摩擦によるエネルギー損失の減少を大目標とし，界面摩擦と同じダイナミクスに従う超伝導体磁束量子格子をモデル系として利用して問題攻略の糸口を探るのを大目的としている。従って，超伝導体磁束量子が運動することによる複雑なエネルギー機構を解明することができれば，より一般的に摩擦によるエネルギー損失の減少につなげることが可能である。