X-ray diffraction analysis on 2223 Tl-oxide single crystals
1989; Elsevier BV; Volume: 161; Issue: 4 Linguagem: Inglês
10.1016/0921-4534(89)90086-5
ISSN1873-2143
AutoresTsuyoshi Kajitani, Kenji Hiraga, Satoru Nakajima, Masae Kikuchi, Yasuhiko Syono, Chizuko Kabuto,
Tópico(s)Inorganic Fluorides and Related Compounds
ResumoSingle crystals of superconducting oxide Tl2−xBa2+yCu3O10−z with x∼0.4, y∼0.4 and z∼0 were synthesized by the flux growth method. Mixtures of oxide powders having a nominal metal ratio Tl/Ba/Ca/Cu at 2/2/2/3 or 2/2/3/4 were heated at 1193 K in a pure oxygen atmosphere at 1 atm for 1 h and then cooled slowly. Crystal structures at room temperature, 180 K and 130 K were investigated by means of 4-circle X-ray diffraction measurement. Splitting of the oxygen site at 4e (0 0 z) with z∼0.28 to 16n(x 0 z) or 16m(x x z) sites with x∼0.05 and z∼ 0.28 in the Tl-O layer is observed in some crystals. At 130 K and 180 K, the O4-site seems to split vertically into “dumbbell” sites. At the same temperatures, CuO5 pyramids are compressed vertically, suggestive of a charge transfer from the Tl-O double layer to the pyramid layer.
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