Fe置換YBCO系における斜方晶相の安定化と超伝導特性(2)

微視的構造

抄録

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.