Texture of Y- and Bi-HTSC and Methods for its Determination
| Autor: | A. A. Babareko, V. F. Shamray, Yu.V. Efimov, T. M. Frolova, E. A. Myasnikova |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
chemistry.chemical_classification
High-temperature superconductivity Chemistry Annealing (metallurgy) Mineralogy General Chemistry Crystal structure Pole figure Condensed Matter Physics law.invention Crystallography law Lattice (order) General Materials Science Orthorhombic crystal system Inorganic compound Diffractometer |
| Zdroj: | Crystal Research and Technology. 26:623-630 |
| ISSN: | 1521-4079 0232-1300 |
| DOI: | 10.1002/crat.2170260515 |
| Popis: | Investigation of the texture of Y- and Bi-HTSC materials by X-ray techniques involves certain difficulties owing to the peculiarities of their crystal structure which causes the arrangement of reflexes in dense groups and practically precludes the formation of a pole figure from an isolated reflex. The texture of Y- and Bi-HTSC materials has been investigated by constructing direct pole figures in an automatic texture diffractometer DAPT YM 1 in CuKα emission from groups of reflexes which are unresolvable under the test conditions. The choice of groups of reflexes was dictated by the type of texture formed. With a basal texture of packing of powders, the following groups have turned out to be the most suitable for the YBa2Cu3O7–x phase (123): (013) + (110) + (103), 2θ = 32.3 – 32.8o and (014) + (005) + (104), 2θ = 38.5 – 38.8o. They include the reflexes which are structural and superstructural relative to a bcc subcell with a rather slight orthorhombic distortion, with its tripling along the “c” axis forming a cell of (123) compound. For the Bi2Sr2CaCu2O8 phase, there have been used the groups of reflexes (008) + (111) + (1.4/54), (0.0.10) + (1.6/5.4) + (0.9/5.1), (0.0.12) + (1.6/5.8) + (204) + (119). (115) + (1.6/5.4) + (0.1/5.9), and (117) + (0.9/5.1) + (1.6/5.6) + (1.4/5.8), 2θ with respectively 23.2 – 24.0o, 29.1 – 29.7o, 35.1 – 35.2o, 36.5 – 28.4o, and 29.7 – 31.4o. They also include reflexes from the lattice constructed by multiplication of a perovskite cell with α = 5.40 A, b = 5.41 A and c = 30.6 A along the “b” axis. Y-HTSC-based materials also contain a component of shear texture which is close to such a texture in bcc metals. The texture of Y- and Bi-HTSC materials is relatively stable in hightemperature annealing. The nature of the effect of annealing at moderate temperature is different. Russian text ignore. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text