Structure analysis of the twin-free orthorhombic YBa{sub 2}Cu{sub 3}O{sub 7-x} single crystals
- Superconductivity Research Laboratory, Tokyo (Japan); and others
The electron density maps of the twin-free orthorhombic YBa{sub 2}Cu{sub 3}O{sub 7-x} single crystal were calculated from the refinement of X-ray structure analysis. The YBa{sub 2}Cu{sub 3}O{sub 7-x} single crystal was grown by the top-seeded crystal pulling method. Uniaxial pressure was applied in the oxygen annealing process to manufacture a twin-free orthorhombic single crystal. The crystal structure of YBa{sub 2}Cu{sub 3}O{sub 7-x} with a superconducting transition temperature of 91 K was determined by a four-circle X-ray diffractometer. Crystal data are as follows: M{sub r}, 666.4; orthorhombic; Pmmm; a=3.8278(7), b=3.8952(7), c= 11.711(2) {Angstrom}; V = 174.61(5) {Angstrom}{sup 3}; Z = 1: D{sub x} = 6.317 Mg{sup {minus}3} {Lambda}(MoK{alpha}) = 0.71069 {Angstrom}; {mu}(MoK{alpha}) = 282.77 cm{sup {minus}1}. The final values of the weighted reliability factor (R{sub w}) and unweighted factor (R) were 0.031 and 0.026, which enables the analysis of Fourier difference maps. In the Fourier difference maps, it was found that two electrons in the 3d{sub z}{sup 2} orbital of Cu2 are not dumbbell-like but are localized as a lone pair and that the inclined electron density around the O2 atoms gives a polarization along the c axis but not around the O3 atom.
- OSTI ID:
- 269888
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 122; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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