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Domain Structures in Perovskite‐Type Lanthanum Magnesium Titanate Ceramics
Author(s) -
Kipkoech Erick Rop,
Azough Feridoon,
Freer Robert
Publication year - 2005
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.1551-2916.2005.00128.x
Subject(s) - crystallography , octahedron , perovskite (structure) , lanthanum , monoclinic crystal system , materials science , superlattice , transmission electron microscopy , crystal structure , crystal twinning , space group , phase (matter) , superstructure , diffraction , x ray crystallography , chemistry , inorganic chemistry , microstructure , physics , optics , nanotechnology , optoelectronics , organic chemistry , thermodynamics
La(Mg 1/2 Ti 1/2 )O 3 ceramics were prepared using a conventional solid‐state reaction route. X‐ray diffraction analysis revealed that La(Mg 1/2 Ti 1/2 )O 3 possesses a distorted perovskite structure consisting of both in‐phase and anti‐phase tilting accompanied by anti‐parallel shifting of La 3+ cation. Superlattice reflections, indicative of 1:1‐type ordering of Mg 2+ and Ti 4+ cations in the octahedral sites, were observed. The crystal symmetry was deduced to be monoclinic with P 2 1 / n space group (No. 14). Transmission electron microscopy analysis revealed two types of twin domains, classified according to the symmetry elements relating adjacent domains. Twin domains with specific orientations, related by mirror operations along {112} and (110) planes, were identified. La(Mg 1/2 Ti 1/2 )O 3 exhibited a high density of dislocations that interact with the twin boundaries resulting in incoherent twin interfaces. In addition, two morphologically distinct anti‐phase domains were observed resulting from (i) off‐center displacement of the La 3+ cations, and (ii) 1:1 ordering of the B‐site sublattice.