Orthorhombic (II) superstructure phase in oxygen-deficient YBa2Cu3O7−δ prepared by quenching

Abstract

The oxygen-ordered orthorhombic (II) superstructure phase in oxygen-deficient ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ was successfully prepared by a metal-block-quenching method. The orthorhombic (II) phase was found to be a single phase with a $T_c$ of ∼60 K at around δ=0.5. Electron diffraction revealed the doubling of the shorter axis (a axis) of the orthorhombic structure in this phase. These results can be interpreted by the structure model that every other Cu-O chain is missing on the Cu(1) plane of the orthorhombic structure at the composition of δ=0.5.