Effects of a controlled over-pressure process on the critical current properties in Bi-2223 tapes

This is the authors' abstract. We don't add key points for this paper.

Critical current properties in Bi-2223 superconductor were investigated in detail for silver-sheathed tapes fabricated by the usual process in a normal pressure, the previous controlled over-pressure (CT-OP) process and the recently improved CT-OP process at the final heat treatment. It was shown that the critical current density, the irreversibility field and the n -value were remarkably improved by application of the CT-OP process. The results were analysed using the flux creep-flow model to seek the reason for the improvements. It was found that the grain connectivity and the flux pinning strength were improved by the previous and recent CT-OP processes, respectively. The possibility of further improvements of the critical current properties in Bi-2223 tapes is discussed.