Continuum vs. discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+delta disks

TitleContinuum vs. discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+delta disks
Publication TypeJournal Article
Year of Publication2009
AuthorsConnolly MR, Milosevic MV, Bending SJ, Clem JR, Tamegai T
Journal TitleEpl
Date Published01/01
ISBN Number0295-5075
Accession NumberISI:000263692500029
Keywordsphase-transitions, superconductors

Scanning Hall probe and local Hall magnetometry measurements have been used to investigate flux distributions in large mesoscopic superconducting disks with sizes that lie near the crossover between the bulk and mesoscopic vortex regimes. Results obtained by directly mapping the magnetic induction profiles of the disks at different applied fields can be quite successfully fitted to analytic models which assume a continuous distribution of flux in the sample. At low fields, however, we do observe clear signatures of the underlying discrete vortex structure and can resolve the characteristic mesoscopic compression of vortex clusters in increasing magnetic fields. Even at higher fields, where single-vortex resolution is lost, we are still able to track configurational changes in the vortex patterns, since competing vortex orders impose unmistakable signatures on "local" magnetisation curves as a function of the applied field. Our observations are in excellent agreement with molecular-dynamics numerical simulations which lead us to a natural definition of the lengthscale for the crossover between discrete and continuum behaviours in our system. Copyright (C) EPLA, 2009

URL<Go to ISI>://000263692500029