Nature of heavy-atom disordering in the YBa2Cu3O6.8 (1.5 at % Ce) single crystal: X-ray photoelectron spectroscopy

Abstract

Photoelectron spectroscopy was used to study nonstoichiometric 123 single crystals in the initial state and after annealing at 200°C in different atmospheres (vacuum, argon, and air). The main cause for the disordering of heavy atoms (Y and Ba), which occurs during annealing in an argon atmosphere and air, was determined by a comparative analysis of the structure and spectra. The disorder is caused by the OH− group that penetrates into the lattice of the compound through oxygen-vacancy chains.