Fabrication and transport AC losses of (Bi,Pb) 2223 multifilamentary tapes with resistive barriers

The Ag-sheathed (Bi,Pb)-2223 multifilamentary tapes with different filament distribution and resistive barriers have been fabricated by powder-in-tube (PIT) method. A rectangular deformation process by using a four-roller machine was applied to fabricate the multifilamentary wires. Bi-2201 and Ag-Cu alloy sheets were introduced into the tape as resistive layers to decrease the coupling between filaments. The transport ac losses were measured on these tapes at 77K with power frequency between 50Hz and 1000Hz. The results indicated that the behaviors of transport ac losses are influenced by both filament distribution and resistive barrier. Introduction of resistive barriers to divide the tape into several thin strips is effective to reduce the transport ac losses. For the prepared 39 filament tapes, when the resistive layers are configured parallel to the tape surface, the transport ac losses at 50Hz measured at 77K are greatly reduced compared to those of 37 filament tape without barriers fabricated by a conventional PIT method.