NOVEL POLYMER-SOLUTION SYNTHESIS OF THE 110-K SUPERCONDUCTING PHASE IN THE BISMUTH SYSTEM

A simplified and highly efficient route to the 110 K (Bi1-xPbx)2Sr2Ca2 Cu3O10+delta superconductor has been developed, based on the use of po lyethylenimine aqueous solutions containing the corresponding metal ac etates. Characterization of the starting solutions by UV-vis spectrosc opy has contributed to the optimization of the synthetic procedure, wh ereas IR spectroscopy and TGA results, combined with XRD patterns, pro vide valuable information on intermediates. Ac magnetic susceptibility studies are consistent with XRD results, indicating the presence of t he (Bi1-xPbx)2Sr2CaCu2O8+delta' 80 K superconducting phase before fina l sintering. Improved sintering conditions result in a nearly single-p hase 110 K superconductor. In contrast to other solution methods, the use of polyethylenimine as active matrix agent gives rise to homogeneo usly sized but relatively large (ca. 20 mum) particles.