Crystal Structure of Ba2ErCu3O7-x Determined by Neutron Powder Diffraction

Abstract
The crystal structure of the high-T c superconductor Ba2ErCu3O7-x has been determined by Rietveld analysis of TOF neutron powder diffraction data. The compound belongs to space group Pmmm and is isomorphic with the orthorhombic form of Ba2YCu3O7-x . The Ba and Er atoms have an ordered arrangement in a Ba-Er-Ba sequence along the c-axis. Oxygen atoms on the z=1/2 plane are missing, while one of the oxygen sites on the z=0 plane is selectively occupied.