DYNAMIC RESISTANCE AND CRITICAL-CURRENT DISTRIBUTION IN HIGH-J(C) BSCCO AG TAPE/

The variation of the dynamic resistance R-d with direct current I-D le ss than or equal to 3A has been studied for an Ag-clad (Bi,Pb)(2)Sr2Ca 2Cu3O10+y tape with J(c)(77K)=29000A/cm(2) in the temperature range 64 -106K and magnetic field B less than or equal to 1.5T. The employed me thod yields the V-I curves with subnanovolt resolution. The V-I curves (V less than or equal to 50 mu V) indicate three different dissipatio n regimes. The onset of strong dissipation (V>10nV) probably reflects the percolative transition of the intergranular weak links into the re sistive state.