X-Ray and Neutron Powder Diffraction Studies of (Ba1-xSrx)Y2CuO5

Published

May 18, 2006

Author(s)

Zhi Yang, Winnie K. Wong-Ng, James A. Kaduk, Qingzhen Huang, Lawrence P. Cook

Abstract

This paper reports the results of the crystallography and crystal chemistry investigation of the (Ba1-xSrx)Y2 CuO5 ( green phase ) solid solution series by x-ray powder diffraction (XPD) and neutron powder diffraction (NPD) methods. The single phase region of (Ba1-xSrx)Y2 CuO5 was determined to be 0 ?x ? 0.3 (prepared at 810?C in 100 Pa pO2) and 0 ?x ? 0.7 (prepared at 930?C in air). All single phase (Ba1-xSrx)Y2 CuO5 samples are isostructural to BaY2CuO5 and can be indexed using an orthorhombic cell with the space group Pnma. Lattice parameters, a, b, c and the cell volume, V, of the (Ba1-xSrx)Y2 CuO5 members decrease linearly with increasing Sr substitution (x) on the Ba site. The general structure of (Ba1-xSrx)Y2 CuO5 can be considered as having a 3-dimensional interconnected network of [YO7], [(Ba,Sr)O11], and [CuO5] polyhedra. The copper ions are located inside distorted [CuO5] square pyramids. These pyramids are connected by the [Y2O11] groups that are formed from two monocapped [YO7] trigonal prisms sharing a triangular face. The Ba2+ atoms are found to reside in distorted 11-fold coordinated cages. The oxygen sites are essentially fully occupied. X-ray reference powder reference patterns of two members of the series, (Ba.3Sr.7)Y2 CuO5 and (Ba.7Sr.3)Y2 CuO5, were prepared for inclusion in the Powder Diffraction File (PDF).

Citation

Powder Diffraction

Volume

21

Issue

3

Pub Type

Journals

Keywords

(Ba_1-xSr_x)Y₂CuO₅, crystal structure and crystal chemistry, Rietveld refinements, x-ray and neutron powder diffraction, x-ray reference

Citation

Yang, Z. , Wong-Ng, W. , A., J. , Huang, Q. and Cook, L. (2006), X-Ray and Neutron Powder Diffraction Studies of (Ba_1-xSr_x)Y₂CuO₅, Powder Diffraction (Accessed May 4, 2024)