SYNTHESIS OF YBA2CU3O7-DELTA - BAPBO3 COMPOSITES

Bulk composites of YBa2Cu3O7-delta superconductors with perovskite oxi de BaPbO3 added in weight percents (wt.%) of 5 similar to 30% were pre pared at temperatures of 900 similar to 1000 degrees C by the conventi onal solid-state reaction method. Pellets sintered at temperatures bet ween 950 degrees C and 960 degrees C showed a relatively high mass den sity and a large grain growth behavior. Scanning electron microscopy a nd electron microprobe analysis showed that slightly Yttrium-deficient rectangular-shaped YBa2Cu3O7-delta grains of up to 25 x 100 mu m(2) w ere embedded in the BaPbO3 matrix. The temperature dependences of the resistance and the ac-susceptibility also indicated that the inter-gra nular property eras significantly improved for the sample with 25 wt.% of BaPbO3 and sintered at a temperature of 960 degrees C. The composi tes may have improved current transport governed bg the superconductor -normal metal-superconductor type behavior of the inter-granular Josep hson couplings.