Structure of the single-phase high-temperature superconductor YBa2Cu3O7-δ.

We have determined the crystal structure of the single-phase stoichiometric high-temperature superconductor in the Y-Ba-Cu-O system using high-resolution neutron powder diffraction. This compound has an orthorhombic structure with space group Pmmm and lattice constants a=3.8231 Å, b=3.8864 Å, and c=11.6807 Å. The structure consists of ‘‘dimpled’’ CuO2 layers in the a-b planes loosely bonded by one-dimensional fencelike square-planar CuO3 chains in the b-c planes. [ABSTRACT FROM AUTHOR]