CA DOPED YBASRCU2.5B0.5-XSXOZ SERIES - COMBINATION EFFECT OF THE CATION AND OXYANION DOPING

A series of compounds (Y-0.6,Ca-0.4)BaSrCu2.5B0.5-xSxOz (0.0 less than or equal to x less than or equal to 0.5) were synthesized using the s olid state reaction method. The effects of calcium substitution on pha se composition and crystal structure and superconductivity are studied . The combination of the cation and oxyanion substitutions, Y3+ by Ca2 + and [BO3](3-) by [SO4](2-), can easily induce superconductivity and T-c increase of 39-43 K can be obtained in the series. Compared with r elated Ca-free series, we can draw the conclusion that the combination of cation and oxyanion doping is superior to single doping in hole pr oviding ability. (C) 1998 Elsevier Science B.V.