SYNTHESIS AND PROPERTIES OF A BI2SR2CACU2OX-BATIO3 COMPOSITE POWDER

A powder of nominal composition 4 moi Bi2Sr2CaCu2Ox (Bi-2212) +1 mol B aTiO3 was prepared from acetates by a sol-gel method. When compared wi th a conventional Bi-2212 powder, the composite powder was less phase pure, containing significant concentrations of Bi2Sr2CuOx, Cu-free pha ses, and CuO. Electron microscopy revealed the presence of nanometre-s cale precipitates within many of the superconductor grains in the comp osite powder. Although these precipitates were uniformly distributed i n only some of the superconducting grains, enhancement of flux pinning at 6 K was attributed to their presence.