Examination of Sorption-Desorption of Oxygen on YBa2Cu3O7-x Superconducting Oxide by TPD Technique

Abstract
Temperature programed desorption (TPD) spectra of oxygen from YBa2Cu3O7-x compounds with different oxygen contents are reported in connection with their superconductivities. Superconducting orthorhombic samples (x<ca. 0.5) with a T c,end of ca. 90 K were found to have two desorption peaks (Peak I centered at 550°C and Peak II centered at ca. 660°C), while tetragonal samples (x>ca. 0.5) showing semiconductive behavior in the temperature range above 77 K had only Peak II. This implies that the oxygen desorbed as Peak I from orthorhombic samples is deeply correlated with the superconductivity.