Superconductivity of the Ba–Y–Cu–O System in the Liquid Nitrogen Temperature

The oxide compounds of BaxY1-xCuO3-y (x=0.3–0.5) have been successfully prepared. The zero resistance temperature of the samples is at 91.5K, with Tc onsets higher than 100K. ac magnetic susceptibility measurements show that the superconducting phase at 82K is not less than 85% in volume.