Synthesis and properties of the Y(Ba 1−xSr x) 2Cu 3−0.15xMo 0.15xO 7−z superconductors

Abstract

We have achieved the preparation of the Y( Ba 1− x Sr x ) 2 Cu 3 O 7 compounds with x ranging from 0 to 1 by substituting a small amount of Cu with Mo. It was observed that the superconducting transition temperature, T c, first decreases linearly with Sr-content until x0.4, where a sharp drop in T c occurs. The T c for the sample with x=0.1 is about 40 K. X-ray structure analysis shows that a sharp drop in T c at a critical concentration corresponds to the crystal change from orthorhombic to tetragonal.