Determination of Space Group and Refinement of Structure Parameters for La₂CuO_4-δ Crystals

Abstract

The space group in the orthorhombic phase of La 2 CuO 4-δ was confirmed to be Cmca for both as grown and deoxygenated crystals by using conventional and convergent beam electron diffraction together with high resolution neutron powder diffraction methods. The Rietveld refinements of neutron powder diffraction data determined the structural parameters. Slight differences in lattice constants, positional parameters and occupation factor for oxygen atoms were found between the two crystals.