GRAIN-GROWTH ENHANCEMENT IN SILVER-DOPED YBA2CU3O7-X SUPERCONDUCTOR

The effects of silver addition on the microstructural and superconducting properties of YBa2Cu3O7-x (YBCO) have been investigated. It was found that the microstructure of silver-doped YBCO samples is characterized by highly oriented platelet-like grains (up to 3 mm x 0.5 mm x 15-mu-m). The superconducting transition temperature T(c) (R = 0) is decreased with increasing wt% of silver. The critical transport density (J(cT)) is, however, found to be improved (up to two orders of magnitude) in the doped materials (J(cT) (T = 77 K and H = 0 T) = 1250 A cm-2). It is believed that the addition of silver lowers the melting temperature of the system and thereby enhances the decomposition of the compound and promotes grain growth during solidification.