NEW HIGH-TC SUPERCONDUCTOR - (IN,PB,CU)SR2(CA,Y)CU2O7-DELTA

Bulk superconductivity was observed in the new system (In(x)Pb(0.75-x)Cu0.25)Sr2(Ca0.5Y0.5)Cu2O7-delta. An increase in indium doping, 0 less-than-or-equal-to x less-than-or-equal-to 0.2, into the Pb sites results in an increase in the superconducting transition temperature T(c) from 45 K for x = 0 to 60 K for x = 0.2. For nominal compositions x > 0.2, a decrease in T(c) was observed and an increase in the concentration of an impurity phase. From the results of the x-ray diffraction and energy-dispersive spectrometry, we identify the phase responsible for the superconductivity to be [In0.06(1)Pb0.69(1)Cu0.25]Sr1.99(7)[Ca0.47(1)Y0.53(2)]Cu2O7-delta; this phase resulted from the synthesis of a sample of nominal composition (In0.2Pb0.55Cu0.25)Sr2(Ca0.5Y0.5)Cu2O7-delta.