Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks

Malcolm R Connolly, M V Milosevic, Simon J Bending, J R Clem, T Tamegai

Research output: Contribution to journalArticle

Abstract

The magnetic properties of a superconducting disk change dramatically when its dimensions become mesoscopic. Unlike large disks, where the screening currents induced by an applied magnetic field are strong enough to force vortices to accumulate in a 'puddle' at the centre, in a mesoscopic disk the interaction between one of these vortices and the edge currents can be comparable to the intervortex repulsion, resulting in a destruction of the ordered triangular vortex lattice structure at the centre. Vortices instead form clusters which adopt polygonal and shell-like structures which exhibit magic number states similar to those of charged particles in a confining potential, and electrons in artificial atoms. We have fabricated mesoscopic high temperature superconducting Bi2Sr2CaCu2O 8+ disks and investigated their magnetic properties using magneto-optical imaging (MOI) and high resolution scanning Hall probe microscopy (SHPM). The temperature dependence of the vortex penetration field measured using MOI is in excellent agreement with models of the thermal excitation of pancake vortices over edge barriers. The growth of the central vortex puddle has been directly imaged using SHPM and magic vortex numbers showing higher stability have been correlated with abrupt jumps in the measured local magnetisation curves.
Original languageEnglish
Article number052039
JournalJournal of Physics: Conference Series
Volume150
Issue number5
DOIs
Publication statusPublished - 2009

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vortices
magnetic properties
microscopy
scanning
probes
confining
destruction
charged particles
screening
penetration
magnetization
temperature dependence
high resolution
curves
magnetic fields
excitation
atoms
electrons
interactions

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Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks. / Connolly, Malcolm R; Milosevic, M V; Bending, Simon J; Clem, J R; Tamegai, T.

In: Journal of Physics: Conference Series, Vol. 150, No. 5, 052039, 2009.

Research output: Contribution to journalArticle

Connolly, Malcolm R ; Milosevic, M V ; Bending, Simon J ; Clem, J R ; Tamegai, T. / Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks. In: Journal of Physics: Conference Series. 2009 ; Vol. 150, No. 5.
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