Crystal Structure of the HoBa2Cu3Ox Superconductor Determined by X-Ray Powder Diffraction

Abstract
The crystal structure of HoBa2Cu3O7 has been determined by Rietveld analysis of X-ray powder diffraction data. The structure is orthorhombic (space group Pmmm) with lattice parameters a=3.8850(1) Å, b=3.8192(1) Å and c=11.6770(2) Å, and isomorphic with YBa2Cu3O7-y . Ordering of Ho and Ba, oxygen deficiency in the z=1/2 plane and selective occupancy of oxygen on the basal plane are the common structural feature of the high T c superconductors.