Crystal Structure of the High Tc Superconductor ErBa2Cu3O7-δ

Abstract
The crystal structure of the high T c superconductor ErBa2Cu3O7-δ has been determined by X-ray powder diffraction combined with the Rietveld analysis. The compound is isostructural with homologous superconductors YBa2Cu3O7-δ and HoBa2Cu3O7-δ. In the orthorhombic structure (space group Pmmm) with lattice parameters a=3.8781(1) Å, b=3.8128(1) Å and c=11.6644(3) Å, Er and Ba are ordered, O in the z=1/2 plane is completely missing and O on the basal plane is deficient.