Superconductivity and Crystal Structure of the Y1Ba2Cu3O7-y-WO3 System

Abstract
The relationship between the superconductivity and crystal structure of the Y1Ba2Cu3O7-y -WO3 system has been studied. Tungsten oxide has various oxidized states, and mixed WO3 in YBCO easily donates its oxygen atoms to YBCO. It is found that the orthorhombic structure of YBCO is modified by mixing of WO3. The lattice constant a increases with increasing concentration of WO3, while the others, b and c, do not significantly change. Although the atomic arrangement in the Cu(2)-O plane of YBCO is consequently modified, superconducting transition temperature T c is kept nearly constant.