Single-Crystal X-Ray Structure Analysis of New Oxide-Superconductor Bi 2 (Sr 1-x Ln x ) 2 (Gd 1-y Ce y ) 2 Cu 2 O 10+z

• Published in: Japanese Journal of Applied Physics 1990-04, Vol.29 (4A), p.L572
• Main Authors: Nakai, Izumi, Imai, Katsuhiro, Arima, Takahisa, Tokura, Yoshinori, Asano, Hajime, Takagi, Hidenori, Uchida, Shin-ichi, Beyers, Robert, Torrance, Jerry B.
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.29.L572

The crystal structure of Bi 2 (Sr 1- x Ln x ) 2 (Gd 1- y Ce y ) 2 Cu 2 O 10+ z (Ln=Gd with x =0.1, y =0.23 and z =0.16 or Ln=Ce with x =0.1, y =0.13 and z =0.16) was determined using the X-ray intensity data of a single crystal. The chemical composition was determined by electron microprobe analysis. The crystal data are as follows: orthorhombic, space group Cmmb, a =5.435(2), b =5.446(1), c =17.826(5) Å, final R factor R w =0.053 for 640 independent observed reflections. The structure is composed of stacking of the Bi-O double layer, a Cu-O sheet of CuO 5 pyramids, and the fluorite-like Ln 2 O 2 layer. Sr is located between the Cu-O sheet and the Bi-O double layer. The crystal has a commensurate type superstructure with unit cell dimensions b ×9 and c ×2 of the subcell: a =5.426(7), b =49.06(2), c =35.66(2) Å. Precession photographs showed orthorhombic symmetry and systematic absences suggested condensed symbols C * c * for the space group of the superlattice. The modulation of the structure was well reflected on the anisotropic motions of the thermal ellipsoids of the component atoms in the average structure.