How to improve critical current properties of Bi2223 and MgB2 tapes

Improvement of critical current properties of well-developed Bi(Pb)2223 superconducting tapes has been still important subject for their extensive applications. On the other hand, enhancement of J(c) up to applicable level at 15-20 K in similar to 5 T is crucial for starting full-scale development of MgB2 materials. In this paper, we propose several effective methods to improve critical current properties of both Bi(Pb)2223 and MgB2 conductors mainly from chemical viewpoints. In particular, Tc of Bi(Pb)2223 was found to be largely enhanced by post-annealing in air. For MgB2, a promising guiding principle for improving flux pinning properties has been just established through various systematic studies. (C) 2007 Elsevier B.V. All rights reserved.