Enhancing the superconducting properties of Y-Ba-Cu-O by CuO/sub 2/ site doping

The incorporation of certain cations such as Zn/sup 2+/ onto the ab-planes of the YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// [123] lattice is known to have effects on the superconducting critical transition temperature. On manipulating the distance between the dopant sites, isolated weak superconducting regions with dimensions comparable to the coherence length of YBCO can be introduced into melt textured large YBCO grains. This paper presents a study using electron microprobe analysis, microscopy and transport property measurements on the processing and the distribution of Zn/sup 2+/ in Zn-YBCO so as to understand as well as optimize the processing conditions, doping level, T/sub c/, flux pinning behaviour and field trapping properties of these materials. These results were correlated with the solidification mechanisms of YBCO as well as the size of weak superconducting regions induced by Zn/sup 2+/.