Microstructure of Lanthanum Magnesium Niobate at Elevated Temperature |
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| Authors: | Hwack Joo Lee Hyun Min Park Yang Koo Cho Hyun Ryu Jong Hoo Paik Sahn Nahm Jae-Dong Byun |
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| Affiliation: | New Materials Evaluation Center, Korea Research Institute of Standards and Science, Taeduk Science Town, Taejon 305–600, Korea;Division of Materials and Metallurgical Engineering, Korea University, Seoul 136–701, Korea |
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| Abstract: | Microstructural studies of the complex perovskite compound La(Mg2/3Nb1/3)O3 (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. |
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| Keywords: | microstructure dielectric materials/properties nibium/niobium compounds |
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