High-T/sub c/ superconductors-based nanocomposites with improved intergrain coupling and enhanced bulk pinning

Heterogeneous sonochemical synthesis was used to modify superconducting properties of granular YBa/sub 2/Ca/sub 3/CuO/sub 7-/spl delta// and Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/. Sonication of liquid-powder alkane slurries produces material with enhanced intergrain coupling and improved current-carrying capabilities. Co-sonication with metals and organometallics results in highly compact nanocomposites with increased magnetic irreversibility. Ultrasonic irradiation of YBa/sub 2/Ca/sub 3/CuO/sub 7-/spl delta// carried under partial oxygen atmosphere produces similar morphological effects and increases superconducting transition temperature due to effective surface saturation with oxygen. Detailed chemical and physical characterization of sonochemically prepared high-T/sub c/ nanocomposites is presented.