Publication
Title
Effect of the substitution $Ba\leftrightarrow Sr$ on the Ga-1222 superstructure : an electron diffraction study
Author
Abstract
 The superstructure of the RE(2)(Sr0.85-xBaxNd0.15)(2)GaCU2O9 compound is found to change significantly with increasing substitution of Ba for Sr. Most of the changes take place in the (Sr0.85-xBaxNd0.15)O-GaO-(Sr0.85-xBaxNd0.15)O lamella, the rest of the basic structure being hardly affected. The structural changes for O less than or equal to x less than or equal to 0.65 are studied by electron diffraction. The arrangement of the chains of GaO4 tetrahedra in the Ba-free compound becomes disordered at x > 0.25. At x similar to 0.65 a rearrangement of the chains in the GaO layers takes place; they form a meandering arrangement, which can be described on a 4a(p) x 2a(p) x c(p) superlattice. This rearrangement is accompanied by ordering of Ba and Sr atoms in the adjacent (ST0.85-xBaxNd0.15)O layers. A simple scheme is proposed to explain the influence of the substitution of Ba for Sr on the linking of the GaO4 tetrahedra and on the geometry of the ''chains'' in the GaO layer.
Language
English
Source (journal)
Chemistry of materials / American Chemical Society. - Washington, D.C.
Publication
Washington, D.C. : 1995
ISSN
0897-4756
Volume/pages
7:9(1995), p. 1709-1715
ISI
A1995RW21200021
Full text (Publisher's DOI)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address