Study on a superconducting micro particle in a magnetic trap

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K03819
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: University of Toyama
• Principal Investigator: Moriwaki Yoshiki 富山大学, 学術研究部理学系, 教授 (90270470)
• Co-Investigator(Kenkyū-buntansha): 小林 かおり 富山大学, 学術研究部理学系, 教授 (80397166)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 微粒子空間捕捉 / 微粒子 / 超伝導 / レーザーアブレーション / 超伝導転移温度 / 超流動ヘリウム / レニウム

Outline of Final Research Achievements

A micro-particle fabricated by laser ablation in superfluid helium can be solely trapped by a quadrupole magnetic field due to the Meissner effect. Using such a single micro-particle, we obtained the results as follows: the angular dependence of the scattering light by the particle could be explained by the Mie scattering model. Due to this analysis, the optical constants of the particle were the same as those of the normal conductors, and in-situ size measurements of the particle in the low temperature condition could be conducted by the light scattering experiments. Analysis of the particle motion in the magnetic field and superfluid helium revealed the magnetic penetration depth of the rhenium superconducting particle. The superconducting critical temperature for the rhenium particle was the highest ever reported. The mechanism for that should be the next research targets.

Free Research Field

量子エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

単一超伝導微粒子の空間捕捉法により，微粒子の超伝導物性，光学物性，超流動ヘリウムの物性測定に現状でどこまで迫れるかが示された。歪などにより超伝導転移温度Tcの増強が報告されているレニウムについて，低温ヘリウム環境で作成した微粒子がこれまでで最も高いTcを実現していることが示された。また，光散乱を用いたin situでの微粒子径測定法は，対象が小さく，作動距離が大きいため光学的な顕微鏡が利用できない場合にも有効に使える点で意義がある。