Lateral distribution of the transport critical current density in Bi(2223) Ag-sheathed tapes

摘要

By using a strip-cutting technique, we directly measured the lateral distribution of the transport critical current density of Ag sheathed Bi(2223) tapes prepared by rolling with overall critical current densities in the range of 23-28 kA/cm~2 at 77K and OT. It has been found that the critical current density of tape strips cut from the sides is reproducibly higher than that of strips from the central part of the sample. For various long tapes prepared by rolling only with a critical current density of 28000 A/cm~2 at 77K and 0T, the local critical current density varies from 23O00 A/cm~2 at the center to 53000 A/cm~2 at the sides of the filament. In all cases, a symmetrical behavior of j_c at both sides of the central axis was observed.