Hamburg 2001 – scientific programme
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TT: Tiefe Temperaturen
TT 13: Transporteigenschaften und kritische Ströme in HTSL
TT 13.1: Talk
Tuesday, March 27, 2001, 17:00–17:15, J
“Vortex-melting front” in thin superconductors — •M.V. Indenbom1,2,3, E.H. Brandt2, C. van der Beek3, and M. Konczykowski3 — 1Institute for Solid State Physics, 142432 Chernogolovka, Moscow district, Russia; email: indenbom@issp.ac.ru — 2Max-Planck-Institut für Metallforschung, D-70506 Stuttgart — 3Laboratoire des Solides Irradiés, Ecole Polytechnique, F-91128 Palaiseau, France
Magneto-optical observations of the first order “vortex melting” phase transition in Bi2Sr2CaCu2Ox single crystals are reinterpreted and simulated numerically. In the presence of pinning this phase transition can be seen in the crystal as a boundary between regions with strong critical current in the high-field phase (“vortex liquid”) and with weak current (“vortex solid”), which corresponds to the so called second magnetization peak. Our analysis shows that in this case in our thin samples the observed second peak front corresponds to the end (i.e. completion, not onset) of the phase transition. Lamellas of both phases appear in the plateau region of the field profile, which precedes this front. At high temperatures the transition can be seen by a sharp jump of the magnetic induction of about 0.1 G. This fact indicates a significant interface energy between “solid” and “liquid”. We analyze wavy instabilities of this interface as a function of the induction gradient in the samples and discuss how to measure its energy.