Effect of Composition Change on Superconducting Properties in a Y-Ba-Cu-O Compound System

Abstract
The superconducting properties in the Y-Ba-Cu-O compound system were investigated by varying the composition ratio Y:Ba:Cu by means of electrical resistivity measurements and X-ray diffractometry. Many compounds exhibited superconductivity and these were located in a comparatively wide composition range, especially in the Cu-rich side, around the ratio of Y:Ba:Cu=1:2:3. The onset temperatures were nearly the same and the measured lattice parameters showed no great differences from those of YBa2Cu3O y .