Novel High-T_c Superconducting Phase of the Y-Ba-Cu-O Compound

Abstract

A novel high- T c superconducting phase is found in the oxide Y-Ba-Cu-O. A sample with nominal composition Ba 0.5 Y 0.5 CuO 3- d shows a sharp superconducting transition at 92.6 K with a width as narrow as 0.9 K. The Electron Probe Micro Analyzer (EPMA) data and the X-ray powder diffraction pattern show that the high T c superconducting phase has the tetragonal oxygen-defect perovskite (ODP) structure with composition Y 2 Ba 4 Cu 6 O 14+ y .