BSCCO tapes

The essential reason for the much lower 7c of the BSCCO tapes compared to monocrystalline films stems from the existence of grain boundaries, which act as barriers to current flow as discussed above. Considering the importance of grain boundaries in a frame of mechanism of the supercurrent flow in BiPb2223 tapes, two models were proposed, the brick-wall [2.116] and railway-switch [2.117] models, which were combined afterwards within the freeway model [2.118]. 

Critical current densities on the order of 10 A cm at 77 K in zero field were measured on BSCCO thin films. In Fig. 4.2-46 the field dependence of 7c of a B12212 film is shown for two temperatures [2.90] and Fig.4.2-47 demonstrates the Jc(B, T) dependence of a B12223 film [2.87]. In magnetic fields aligned parallel to the plane of the film, that is perpendicular to the c axis of the crystal structure, 7c is practically independent on the field strength, even at higher temperatures such as 60 K. The reasons for this behavior are discussed below in connection with the Jc(B, T) correlation of wires and tapes. 

IC -Advanced Superconductors manufactures superconductive wire, cable, and tape for MRI diagnostic systems, high-energy physics, and fusion power research. Products are based on NbTi, NbjSn, BSCCO (Bi-Sr-Ca-Cu-O) 2212/Ag, and BSCCO 2223/Ag multi-fUament wire and tape. 

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