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Structure and Dielectric Properties of the Ba(Mg 1/3 Nb 2/3 )O 3 ‐La(Mg 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.tb02610.x
Subject(s) - solid solution , crystallography , materials science , supercell , dielectric , perovskite (structure) , phase (matter) , analytical chemistry (journal) , chemistry , physics , thunderstorm , optoelectronics , organic chemistry , chromatography , meteorology , metallurgy
A complete range of perovskite solid solutions can be formed in the (1 − x )Ba(Mg 1/3 Nb 2/3 )O 3 ‐ x La(Mg 2/3 Nb 1/3 )O 3 (BMN‐LMN) pseudobinary system. While pure BMN adopts a 1:2 cation ordered structure, 1:1 ordered phases are stabilized for 0.05 ≤ x ≤ 1.0. Dark‐field TEM images indicate that the La‐doped solid solutions are comprised of large 1:1 ordered domains and no evidence was found for a phase‐separated structure. This observation coupled with the systematic variations in the intensities of the supercell reflections supports a charge‐balanced “random‐site” model for the 1:1 ordering. The substitution of La also induces a transformation from a negative to positive temperature coefficient of capacitance in the region 0.25 ≤ x ≤ 0.5.