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Structure analysis of oxygen-deficient TlSr2CuO by neutron diffraction and high-resolution electron microscopy

1994; Elsevier BV; Volume: 221; Issue: 3-4 Linguagem: Inglês

10.1016/0921-4534(94)90231-3

1873-2143

Eriko Ohshima, Masae Kikuchi, Fujio Izumi, Kenji Hiraga, Takeo Oku, Satoru Nakajima, Naoyuki Ohnishi, Yukio Morri, Satoru Funahashi, Yasuhiko Syono,

Microwave Dielectric Ceramics Synthesis

The crystal structure of orthorhombic TlSr2CuOy was determined by Rietveld analysis of neutron powder diffraction data with the aid of electron diffraction and high-resolution electron microscopy. We found that oxygen vacancies are formed along the a-direction in a CuO2−z sheet, which is consistent with a superstructure of twice the subcell along the b-direction. CuO6 octahedra and CuO4 square planes alternate along the b-direction by sharing their corners in accordance with the ordered oxygen vacancies in the CuO2−z sheet. An apical oxygen atom in the CuO6 octahedron is nearer to a TlO layer than an oxygen atom shared by a TlO6 octahedron and the CuO4 plane. A crystal-structure image obtained by high-resolution electron microscopy could be successfully reproduced by computer simulation using structure parameters obtained by neutron powder diffraction.