CRYSTAL STRUCTURE OF Ba3CuRu2O9 AND COMPARISON TO Ba3MRu2O9 (M=In, Co, Ni, AND Fe)

摘要

The crystal structure of Ba3CuRu2O9, determined by powder neutron diffraction, is reported for temperatures of 18-295 K. Structural refinements by powder neutron diffraction for the previously reported compounds Ba3MRu2O9 for M=Fe, Co, Ni, and In are also reported. All structures consist of pairs of face-shared RuO6 octahedra interconnected by corner-sharing MO6 octahedra. For Ba3CuRu2O9, Jahn-Teller distortion of the CuO6 octahedra leads to an orthorhombic symmetry structure of space group Cmcm with a=5.6723(1), b=10.1722(3), and c=14.1575(3) angstroms at 295 K. For Ba3FeRu2O9, site occupancy disorder is found. Magnetic ordering is observed below 100, 105, and 110 K for M=Cu, Ni, and Co, respp. The magnetic structures at low temperatures for M=Co and Ni are described and compared to previous reports. 13 refs.