Writers: Hernandez-Wolpez, M; Martinez-Guerra, E; Jardim, RF; Mune, P
Keywords: high-temperature superconductors; high-tc superconductors; lower critical-field; pure 2223 powders; semi-wet methods; magnetic-field; flux-creep; bi2-xpbxsr2ca2cu3oy compositions; grain-boundaries; rapid synthesis
Abstract: The aim of this review is to give a summary of some hidden features related to penetration, trapping, and relaxation of the magnetic ﬂux in (Bi,Pb)-2223 granular superconductors. The discussion is based on experimental and theoretical results obtained in samples prepared under different conditions and by different research groups. Fundamental concepts such as granularity and grain boundaries (GB), superconducting levels, types of vortices, and microstructural characteristics of (Bi,Pb)-Sr-Ca-Cu-O superconductors are invoked for supporting the discussion. As conclusions we focus on the main insufﬁciencies in the treatment and understanding of the phenomena mentioned above. We also propose some experiments for improving the understanding of the general physical features of granular superconductors.