Crystal Structure of Magnetic Superconductor FeSr_2YCu_2O_<6+δ>

概要

論文の詳細を見る
The FeSr_2YCu_2O_<6+δ> compound with a Ba_2YCu_3O_<6+δ>-type structure exhibits superconductivity around 50K, only when it is properly annealed in N_2 atmosphere and subsequently in O_2 atmosphere. The compound without N_2-annealing, however, does not exhibit superconductivity. This compound consists of a sequence of alternating CuO_2 double sheets with nanometer-scale separation as those in high-T_c superconductors, and FeO_δ sheets similar to that in the SrFeO_<3-δ> magnetic compound. Neutron diffraction study shows that both N_2-annealing and subsequent O_2-annealing cause ordering of Cu and Fe, and that both O_2-annealing and subsequent oxidization under high-O_2 pressure supply the charge. However, the charge was distributed not only to the CuO_2 sheet but also the FeO_δ sheet. The bond valence sum calculation indicates that charges distributed to the FeO_δ sheet more than to the CuO_2 sheet in the superconducting sample.
社団法人日本物理学会の論文
2002-03-15