La(Mg$_{2/3}$Nb$_{1/3}$)O$_3$ 세라믹의 결정구조 |
심동민, 송용원, 조범준1, 백종후, 남산2, 김경용3, 변재동 |
고려대학교 재료공학과 1고려대학교 통신시스템 기술학과 2고려대학교 재료공학 3한국과학기술원 세라믹공정센터 |
Crystal Structure of La(Mg$_{2/3}$Nb$_{1/3}$)O$_3$ Ceramics |
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ABSTRACT |
Crystal structure of La(Mg2/3Nb1/3)O3 has been analyzed by high resolution transmission electron microcopy (HRTEM) and Rietveld refinement using X-ray powder diffraction pattern. La(Mg2/3Nb1/3)O3 has 1:1 ordered monoclinic structure P21/n contrarily to the results of previous works which suggested 1:1 romobohedral or orthorombic structure. The lattice parameters of La(Mg2/3Nb1/3)O3 are a=5.6004 $AA$, b=5.6414 $AA$ c=7.9346 $AA$ and $beta$=89.9819$^{circ}$Monoclinic La(Mg2/3Nb1/3)O3 is distorted by in-phase and anti-phase tilting of octahedra with the a-,a-,c+ tiliting system. Anti-parallel shift of A-site cations was also found in La(Mg2/3Nb1/3)O3 |
Key words:
Microwave, La(Mg$_{2/3}$Nb$_{1/3}$)O$_3$, HRTEM, Rietveld Refinement, Tilting of Oxygen Octahedra. |
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