On the structure of the superconducting ortho-II phase of YBa{sub 2}Cu{sub 3}O{sub 6.51}

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Journal of Electronic Materials

DOI:https://doi.org/10.1007/BF02818065· OSTI ID:433423

Zeiske, T; Grybos, J; Kubanek, F ^[1]

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1. Hahn-Meitner-Institut Berlin (Germany); and others

From the intensities of superstructure reflections, the structure of the ortho-II phase in YBa{sub 2}Cu{sub 3}O{sub 6.51(5)} (T{sub c} = 55.8K) was determined by single crystal x-ray diffraction. In the basal plane of the 2a x b x c supercell, the oxygen atoms order to alternating Cu-O-Cu and Cu-Cu chains. Due to the oxygen order, the barium and yttrium atoms are displaced in (100) direction in an antiferrodistortive way (Ba-shift: 0.046{Angstrom} toward the Cu-O-Cu chains, Y-shift: 0.008{Angstrom} toward the Cu-Cu chains). The apex oxygen and copper atoms of the superconducting planes are displaced in (001) direction. The Ba displacements are confirmed by anomalous scattering near the Ba-K absorption edge observed by synchrotron x-ray diffraction. A rigid ion model shows that the cation displacements stabilize the ortho-II structure by reducing its lattice energy.

• Sponsoring Organization: USDOE
• OSTI ID: 433423
• Journal Information: Journal of Electronic Materials, Journal Name: Journal of Electronic Materials Journal Issue: 10 Vol. 22; ISSN JECMA5; ISSN 0361-5235
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
COPPER OXIDES
CRYSTAL STRUCTURE
HIGH-TC SUPERCONDUCTORS
YTTRIUM OXIDES