Neutron powder diffraction study of the crystal structure of YSr[sub 2]AlCu[sub 2]O[sub 7]

Journal Article · Mon Feb 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1064· OSTI ID:6516322

Huang, Q; Santoro, A ^[1]; Sunshine, S A ^[2]; Cava, R J ^[3]

---

1. National Inst. of Standards and Technology, Gaithersburg, MD (United States)
2. Raychem Research and Development, Menlo Park, CA (United States)
3. AT T Bell Laboratories, Murray Hill, NJ (United States)

The structure of YSr[sub 2]AlCu[sub 2]O[sub 7] has been analyzed by neutron powder diffraction techniques. This compound crystallizes with space group P4/mmm symmetry and with lattice parameters a = 3.8646(1), c = 11.1139(3) [Angstrom]. The general structural features of YSr[sub 2]AlCu[sub 2]O[sub 7] are similar to those found for the 123 superconductor YBa[sub 2]Cu[sub 3]O[sub 6+[delta]], and in particular the sequence of layers is the same in the two materials, with SrO substituting for BaO. The Al ions substitute for the copper ions of the chain sites of the 123 parent structure and have tetrahedral coordination. The tetrahedra form chains propagating along the a and b axes on the basal plane of the unit cell. Thus the structure is made of short-range domains within which the local symmetry is orthorhombic. All the oxygen atoms in this compound have a disordered configuration around the specialized positions of the 123 structure. This arrangement results in tilting of the CuO[sub 5] pyramids and in significant distortions of the coordination polyhedra of the other cations. 6 refs., 5 figs., 4 tabs.

• OSTI ID: 6516322
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 102:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATIONS
CHAINS
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER IONS
COPPER OXIDES
CRYSTAL STRUCTURE
DIFFRACTION
IONS
LATTICE PARAMETERS
LAYERS
NEUTRON DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES