論文 - 後藤　秀徳

Observation of vortex expulsion in mesoscopic superconducting disks 査読

H. Goto, K. Kono

Physica E: Low-Dimensional Systems and Nanostructures   40 ( 2 )   339 - 342   2007年12月

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

We have studied vortex expulsion processes in a superconducting disk with a multi-terminal Hall sensor. Various combinations of these terminals enabled us to obtain an angular dependence of magnetization in the disk. The resolution of π/4 allowed us to identify three vortices. With a decrease in magnetic fields, vortices were expelled one by one from the different edges. After each expulsion the residual vortices were reconfigured in a complicated way. Their equilibrium positions changed with lowering temperatures. These results are interpreted in terms of repulsively interacting particles in the confinement and the pinning potential. The latter potential is found to be important at low temperatures. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physe.2007.06.021

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Magnetic response of a mesoscopic superconducting disk surrounded by a normal metal 査読

Hidenori Goto, Kazuhito Tsukagoshi, Kimitoshi Kono

LOW TEMPERATURE PHYSICS, PTS A AND B   850   753 - +   2006年

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

Magnetic response of a superconductor/normal-metal (S/N) concentric disk is studied by use of a ballistic Hall magnetometer, which enables us to investigate the mutual proximity effects in a single and a micrometer-sized sample. The core of the sample is a type-I superconductor whose diameter is comparable to the coherence length and the magnetic penetration depth. The core and the surround are prepared by an improved double-angle evaporation method to realize their metallic contacts. At T = 1.3 K, the pair breaking effect on the S has been predominant. We have observed the smaller diamagnetic susceptibility, the larger critical field, and the less stable vortex states in the S/N sample than in only S sample. These results are attributed to the suppression of the surface superconductivity, which effectively decreases the diameter of the superconductor.

DOI： 10.1063/1.2354923

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