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Cation Ordering Transformations in the Ba(Zn 1/3 Nb 2/3 )O 3 ‐La(Zn 2/3 Nb 1/3 )O 3 System
Author(s) -
Akbas Mehmet A.,
Davies Peter K.
Publication year - 1998
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1998.tb02450.x
Subject(s) - crystallography , natural bond orbital , trigonal crystal system , perovskite (structure) , microstructure , solid solution , materials science , lanthanum , crystal structure , chemistry , inorganic chemistry , metallurgy , molecule , organic chemistry
Single‐phase perovskites were formed in the (1− x )Ba(Zn 1/3 Nb 2/3 )O 3 ‐( x )La(Zn 2/3 Nb 1/3 )O 3 system for compositions with 0.0≤ x ≤0.6. Although the stability of the trigonal “1:2” ordered structure of the Ba(Zn 1/3 Nb 2/3 )O 3 end member is very limited (0.0≤ x ≤0.05), low levels of lanthanum induce a transformation to a cubic, “1:1” ordered structure that has a broad range of homogeneity (0.05≤ x ≤0.6). Samples with x > 0.6 were comprised of La 3 NbO 7 , ZnO, and a perovskite with x = 0.6. The cubic 1:1 phases were fully ordered and no evidence was found for a compositionally segregated microstructure. These observations could not be reconciled in terms of a “space‐charge” model; rather, they supported a charge‐balanced, “random‐site” structure for the 1:1 cation‐ordered Ba(β 1/2 ′β 1/2 ″)O 3 phases.