XPS Measurement of YBa2Cu3Oy Compounds Heated at Various Temperatures

Abstract
Temperature dependences of XPS spectra of orthorhombic and tetragonal YBa2Cu3O y compounds were measured. Variation of satellite peaks of Cu 2P for the superconducting compound coincided with a change of Cu valence which was deduced from the oxygen content. For the nonsuperconducting compound, no distinct change in XPS spectra was observed up to 770 K. The XPS spectra of O 1S showed three different states of oxygen atoms in the compound. Analyzing the temperature dependence of these peaks, they were attributed to the three oxygen configurations around copper: the octahedral, pyramidal and square planar.