Flux-pinning enhancement in Ag-sheathed Bi-2223 tapes by nanometer-SiC addition

We have studied the influence of nanometer SIC particles on the flux pinning and the magnetization critical current density J(cm) of Ag-sheathed (Bi,Pb)(2)Sr2Ca2Cu3Ox superconducting tapes. The results show that below 40 K SiC particles up to 0.5 wt.% introduce additional flux-pinning centres, and enhance J(cm) to different extent dependent on the temperature and applied magnetic field. For the tapes with SiC addition up to 0.5 wt.%, the magnetization critical current density J(cm) at 5 K in applied fields up to 50 kOe is twice that of the tape without SiC, for both H parallel to c and H parallel to ab. A study of the magnetization decay shows that tape with 0.15 wt.% nanometer SiC particles has a reduced flux-creep rate and increased pinning potential compared with the tape without SiC. The enhanced pinning properties can be attributed to the small SIC particles dispersed in the superconducting matrix and to the secondary defects at the interface between SiC particles and the superconducting matrix created by the introduction of the SiC particles. (C) 1999 Elsevier Science B.V. All rights reserved.