Decrease of screening critical current compared to volume one due to boundary conditions influence on the ordering parameter in ceramic BiPbSrCaCuO HTSC samples

A.A.Kozlovsky, V.P.Seminozhenko, V.F.Khirny

Institute for Single Crystals, National Academy of Sciences of Ukraine, 60 Lenin Ave., 310001 Kharkiv, Ukraine

Received December 24, 1997

Boundary conditions in a HTSC sample of bismuth-lead ceramics have been studied within the temperature region near Tc. Data on changes in the ordering parameter value near the superconductor surface have been obtained by analysing temperature dependences of critical currents determined from volt-ampere characteristics as well as using the magnetic method. The distinction between the ordering parameter values near the sample surface and in its volume has been confirmed in experiment. Temperature dependence of the ratio between ordering parameter values near the surface and in the volume has been determined.

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