Synthesis of New Superconducting Pb-Based 1222 Cuprates Containing Sulfur in the (Pb0.75S0.25)Sr2(Eu2.0−xCex)Cu2Oz System

We have synthesized new Pb-based 1222 cuprates containing sulfur in the (Pb0.75S0.25)Sr2(Eu2.0−x Ce x )Cu2O z system. X-ray diffraction study shows that almost the single 1222 phase samples can be obtained for a considerable wide area of 0.3≤x≤1.2 in the composition of (Pb0.75S0.25)Sr2(Eu2.0−x Ce x )Cu2O z . Next, the sample with x=0.4 after annealing under high-pressure O2 is discovered to show an onset of the resistivity drop at about 31 K and to show an onset of diamagnetic signal at about 29 K. These phenomena clearly indicate that the sample is a new superconductor.