Fabrication and AC transport losses for Ag-sheathed Bi-2223 tapes using rectangular deformation process

Abstract

The AC transport losses in self-field at 77 K have been investigated for the Ag-sheathed Bi-2223 multifilamentary tapes prepared by rectangular deformation process. The rectangular wires with 20 (5 × 4 arrangement) filaments and different aspect ratio of their cross-section were fabricated by two-axial rolling machine, and subsequently they were converted to the tape-form conductors by the one-axial flat rolling and heat treatments. The initial configurations of rectangular wires before applying the flat rolling affect the filament shape near the tape edge in the final tapes. Furthermore, transport loss behaviors for investigated tapes also depend on the initial configurations of rectangular wires, although the main contribution to the losses comes from the hysteresis loss of the superconductor. This may be caused by the difference in filament shape and lateral J c distributions in the cross-section of each tape samples.