SUPERCONDUCTIVITY AND STRUCTURAL-CHANGE IN THE (BI2-YPBY)SR-2(EU2-XCEX)CU2OZ SYSTEM

Superconductivity and crystal structure change have been observed in t he Bi(Pb)-2222 system of (Bi2-yPby)Sr-2(Eu2-xCex)Cu2Oz By substitution of Pb for Bi, the samples easily become superconductors without annea ling under high-pressure O-2 atmosphere. Then, when the Pb content y i s increasing and exceeds 0.5, the crystal structure changes from a pse udotetragonal structure to an orthorhombic one. Interestingly, with in creasing of the y value, the T-c value monotonously increases, while t he superconducting volume fraction shows a maximum at y = 0.5. (C) 199 8 Elsevier Science B.V. All rights reserved.