XPS DOS studies of oxygen‐plasma treated YBa2Cu3O7−δ surfaces as a function of temperature

Monochromatized AlKα XPS has been used to monitor changes in the electronic structure of 123 sintered pellets as a function of temperature (90–650 K). Since 123 surfaces are known to lose oxygen and react with water, a novel procedure was used to prepare the material surface that would be representative of the bulk material. In contrast with published results, we observed drastic DOS modification (i.e. the appearance of a new peak close to the Fermi level at low temperature).