X-ray and neutron diffraction of yttrium–barium–copper–oxide: Modeling diffraction intensity variations produced by surface leaching

Abstract

High normal current fluences have long been reported to produce major changes in the x-ray diffraction pattern of YBa2Cu3O7−x (YBCO). These x-ray diffraction effects have now been shown to result from the removal of barium from the YBCO near-surface lattice together with the formation of a thin barium oxide overlayer. Neutron diffraction reveals that the bulk crystallographic structure remains unaltered by charge fluences of more than 40 million C/cm2, and Auger electron spectroscopy confirms the presence of surface barium enrichment.