Superconductivity, Structure and Oxygen Content of Fe-Doped Ba2YCu3Oy

Abstract
The crystal structure and superconductivity of Ba2Y(Cu1-x Fe x )3O y have been studied along with its compositional analysis, especially that of oxygen. This system shows an orthorhombic-to-tetragonal phase transformation and has been extensively investigated by several groups. In the present study we observed that with an increasing Fe concentration x, the superconducting transition temperature T c decreases slowly correlating with the difference of the lattice constants, b-a, in the orthorhombic phase region and decreases rapidly from x>0.04∼0.05 in the tetragonal phase region, while y is almost constant.