Brett McCarty

Effects of high-intensity ultrasound on Bi2Sr2CaCu2O8+x superconductor

Slurries of powdered Bi2Sr2CaCu2O8+x superconductor in low volatility alkanes were treated with intense ultrasound. Significant enhancements of magnetic irreversibility as well as transport critical current are reported. The effects are dependent on the concentration of the slurry and are optimal for 1.5% wt. slurry loading. Electron microscopy shows that ultrasonic treatment leads to a change in grain morphology and intergrain welding. The observed enhancement of superconducting properties is consistent with the limitations in critical currents in BSCCO superconductor being due to intergrain coupling rather than intragrain pinning strength.

Effects of High Intensity Ultrasound on BSCCO-2212 Superconductor

Slurries of powdered Bi2Sr2CaCu2O8+x superconductor in low volatility alkanes were treated with intense ultrasound. Significant enhancements of magnetic irreversibility as well as transport critical current are reported. The effects are dependent on the concentration of the slurry and are optimal for 1.5% wt. slurry loading. Electron microscopy shows that ultrasonic treatment leads to a change in grain morphology and intergrain welding. The observed enhancement of superconducting properties is consistent with the limitations in critical currents in BSCCO superconductor being due to intergrain coupling rather than intragrain pinning strength.

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.