Bulk superconductivity was observed in the systems (Pb0.75Cu0.25)Sr2(Ca1-xYx)Cu2O7-δ and (InyPb0.75-yCu0.25)Sr2(Ca0.5Y0.5)Cu2O-δ. With decreasing x in (Pb0.75Cu0.25)Sr2(Ca1-xYx)Cu2O7-δ, Tc increases up to 55 K at x=0.1; however this specimen is multiphasic with superconducting Meissner volume fraction of ca. 1.5%. In contrast, the sample with x=0.5 is nearly single phase and has a lower Tc (45 K) and a high superconducting Meissner volume fraction ca. 20.2%. An increase of the indium doping in (InyPb0.75-yCu0.25Sr2(Ca0.5Y0.5)Cu2O7-δ, 0 ≤y≤0.2, results in an increase in the superconducting transition temperature from 45 K for y=0, to 60 K for y=0.2.
ASJC Scopus subject areas