The Stabilization of the Orthorhombic Phase and the Superconducting Properties in YBa₂ (Cu_1-xFe_x)₃O_y Prepared by a New Method.(2)

Microscopic Structure

Abstract

YBa₂(Cu_1-xFe_x)₃O_y with the orthorhombic structure was prepared in the wide composition range (0≤x<0.15) by heating in pure N₂ gas followed by annealing in O₂ gas below 400°C. The stabilization of the orthorhombic phase was discussed in terms of the arrangement of Fe ions in the Cu1-O planes. ⁵⁷Fe Mossbauer measurements were performed on the five samples of YBa₂(Cu_0.96Fe_0.04)₃O_y which were prepared by the different thermal treatments. As the results, Fe ions occupy both Cu1 and Cu2 sites and the substitution of Fe ions for Cu ions in the Cu2 sites is little affected on the superconducting properties of YBa₂Cu₃O_y.