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Microstructure of Lanthanum Magnesium Niobate at Elevated Temperature
Author(s) -
Lee Hwack Joo,
Park Hyun Min,
Cho Yang Koo,
Ryu Hyun,
Paik Jong Hoo,
Nahm Sahn,
Byun JaeDong
Publication year - 2000
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.1151-2916.2000.tb01299.x
Subject(s) - superlattice , lanthanum , transmission electron microscopy , microstructure , materials science , crystallography , niobium , octahedron , magnesium , perovskite (structure) , x ray crystallography , electron diffraction , reflection (computer programming) , diffraction , analytical chemistry (journal) , mineralogy , crystal structure , chemistry , inorganic chemistry , metallurgy , optics , nanotechnology , programming language , physics , optoelectronics , chromatography , computer science
Microstructural studies of the complex perovskite compound La(Mg 2/3 Nb 1/3 )O 3 (LMN) were conducted using transmission electron microscopy (TEM) and X‐ray diffractometry (XRD) at elevated temperatures. 1:1 chemical ordering of B‐site cations and tilting of oxygen octahedra were observed in LMN. Three types of superlattice reflections, [1—2]{111}, [1—2]{110}, and [1—2]{100} were observed at room temperature and at 800°C in electron diffraction patterns. In the XRD experiments, the [1—2]{210} and [1—2]{300} extra peaks disappeared at temperatures >1200°C. However, the intensity of the superlattice [1—2]{111} peak did not change with increased temperature up to 1400°C. These results strongly indicated that the origin of superlattice reflection [1—2]{111} was different from that of the other superlattice reflections. It was mainly caused by the 1:1 chemical ordering of magnesium and niobium atoms. The TEM image observed at 800°C showed the ordered domain structures separated by the antiphase boundaries.