Joint x-ray and neutron refinement of the structure of superconducting YBa2Cu

Abstract

X-ray and neutron powder diffraction data for superconducting orthorhombic ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{x}}$ have been used in a joint refinement to give a room-temperature structure which includes a very precise set of atom positions and thermal-motion parameters. Broadening of the diffraction peaks indicates that these materials are highly strained, and contrary to a number of suggestions in the literature, no evidence is found for any cation disorder.