Structure of Tetragonal YBa₂Cu₃O_5.8

Abstract

A single-phase YBa 2 Cu 3 O 5.8 with a tetragonal symmetry shows a semiconductor-like resistivity down to 4.2 K. The crystal structure of this compound has been determined by the Rietveld profile analysis of neutron powder diffraction data measured at 10 K. The space group P4/mmm is confirmed, and lattice constants are a =3.8607(3) Å and c =11.774(1) Å. The oxygen site 2 g(0 0 0.1553) is fully occupied, but the occupation of the 4i site (1/2 0 0.3786) is 0.91 and that of the 2f site (1/2 0 0) is only 0.07.