Effect of Ba Substitution for Sr in the Pb-based 1212 Cuprate Containing Sulfur of (Pb0.75S0.25)Sr2(Y,Ca)Cu2Oz

We already reported on the synthesis of new Pb-based 1212 layered cuprates containing sulfur in the (Pb(0.75)S(0.25))Sr(2)(Y,Ca)Cu(2)O (z) system. There none of the samples showed superconductivity until after annealing under high O(2) pressure. More recently, we have discovered that the samples could be substituted by Ba for Sr up to x=0.6 in the composition of (Pb(0.75)S(0.25))(Sr(2-x) Ba (x) )(Y(0.4)Ca(0.6)) Cu(2)O (z) . Then if the Ba-substitution is performed for Sr, some of the almost-single phase samples are found to show resistivity drops and magnetic anomalies without annealing under high O(2) pressure. Among the samples, a sample with the nominal composition of (Pb(0.75)S(0.25))(Sr(1.5)Ba(0.5))(Y(0.4)Ca(0.6)) Cu(2)O (z) is found to show the highest onset temperatures of a resistivity drop at about 35 K and a magnetic anomaly at about 31.5 K. These are higher than the highest values for the superconducting Ba-free sample of (Pb(0.75)S(0.25))Sr(2) (Y(0.4)Ca(0.6))Cu(2)O (z) which was annealed under high O(2) pressure.