Superconducting PbBaSrY1-xCaxCu3O7 with a maximum Tc onset at 65 K was synthesized. Single-phase materials were obtained for 0 ≤ x ≤ 0.25 by sintering in a 1% O2-N2 gas at 750-830°C and quenching from 785°C. Superconductivity appeared for x ≥ 0.15 and Tc increased with increasing Ca content. PbBaSrY0.7Ca0.3O7 was confirmed to achieve zero resistance at 37 K with about 45% bulk superconductivity. Superconductivity was considered to occur by hole introduction in CuO2 sheets by substituting Y3+ with Ca2+, the same mechanism as in Pb2Sr2Y1-xCaxCu3O8.
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