Applied Microscopy

Korean Society of Microscopy (한국현미경학회)
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Microstructure Observation of Complex Perovskite (1-x) $(Li_{1/2}Sm_{1/2})TiO_3-x (Na_{1/2}Sm_{1/2})TiO_3$ (LNST) System [2]

복합 페로브스카이트 (1-x) $(Li_{1/2}Sm_{1/2})TiO_3-x (Na_{1/2}Sm_{1/2})TiO_3$ (LNST) system의 미세구조 관찰 [2]

  • Son, JJin-Ok (Department of Materials Science and Engineering, Korea University) ;
  • Nahm, Sahn (Department of Materials Science and Engineering, Korea University) ;
  • Lee, Hwack-Joo (New Materials Evaluation Center, Korea Research Institute of Standards and Science)
  • 손진옥 (고려대학교 공과대학 재료공학부) ;
  • 남산 (고려대학교 공과대학 재료공학부) ;
  • 이확주 (한국표준과학연구원 물질량 표준부)
  • Published : 2004.06.01
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Abstract

Microstructural characteristics of the Complex Perovskite (1-x) $(Li_{1/2}Sm_{1/2})TiO_3-x (Na_{1/2}Sm_{1/2})TiO_3$ (LNST) system have been investigated using the transmission electron microscopy (TEM). When $0.0{\leq}x{\leq}0.6$, the vacancy ordering forming the 1/2 (001) superlattice reflections due to the A-site cation deficiencies has apperaed. It could be confirmed by presence of ABPs. But it was difficult to form the vacancy ordering since vacancy concentration gradually lowered as the amount of the substituted Li ions decrease. Antiphase boundaries (APBs) were presented in microstructures of LNST when $0.8{\leq}x{\leq}1.0$. It was considered that these boundaries were caused by the 1:1 chemical ordering of A-site cations, Na and Sm ions. LNST had not only the antiphase tilting of oxygen octahedron but also the inphase tilting of oxygen octahedron and the antiparallel shift of cations all of them. It could be confirmed by presence of ferroelastic domains

복합페로브스카이트 (1-x) $(Li_{1/2}Sm_{1/2})TiO_3-x (Na_{1/2}Sm_{1/2})TiO_3$ (LNST)의 미세구조를 TEM으로 관찰하였다. $0.0{\leq}x{\leq}0.6$ LNST에서는 A-site 양이온의 결핍에 의한 1/2 (001) 초격자 회절점을 형성하는 vacancy ordering을 갖고 있으며 이는 APB로 확인할 수 있었다. 그러나 x가 증가함에 따라 Li 이온의 양이 적어져서 vacancy ordering 을 만들기 어렵게 된다. $0.8{\leq}x{\leq}1.0$ 조성의 LNST의 미세구조에서도 APB가 관찰되었는데 이는 A-site에서 Na와 Sm 이온간의 1:1 chemical ordering에 의한 것으로 사료된다. LNST 전 조성에서 산소팔면체의 anti-phase tilting과 in-phase tilting 그리고 A-site 양이온의 antiparallel shift가 관찰되었는데, 이들은 ferroelastic domain으로 확인할 수 있었다.

Keywords

References

  1. Barber DJ, Moulding KM, Zhou J, Li MQ: Structural order in $Ba\;(Zn_{1/3}Ta_{2/3})O_3,\;Ba\;(Zn_{1/3}Nb_{2/3})O_3\;and\;Ba\;(Mg_{1/3}Ta_{2/3})O_3$ microwave dielectric ceramics. J Mater Science 32 : 1531 1544, 1997 https://doi.org/10.1023/A:1018574505601
  2. Glazer AM: The Classification of Tilted Octahedra in Perovskites. Acta Cryst B28 : 3384 3392, 1972 https://doi.org/10.1107/S0567740872007976
  3. Glazer AM: Simple Ways of Determining Perovskite Structures, Acta Cryst A31 : 756 62, 1975 https://doi.org/10.1107/S0567739475001635
  4. Itoh M, Inaguma. Y, Jung WH, Chen L, Nakamura T: High lithium ion conductivity in the perovskite type compounds $Ln_{1/2}Li_{1/2}TiO_3$ (Ln = La, Pr, Nd, Sm). Solid state Ionics 70/71 : 203 207, 1994 https://doi.org/10.1016/0167-2738(94)90310-7
  5. Lee HJ, Park HM, Cho YK, Ryu H, Son YW: Microstructural Observations in Barium Clcium Magnesium Niobate. J Am Ceram So 83(9) : 2267 72, 2000
  6. Lee HJ, Ryu H, Park HM, Cho YK, Nahm S: Microstructure Observations in Complex Perovskite $({Na}_{1/2}{Pr}_{1/2})TiO_3$. Korean J Electron Microscopy 32(2) : 157 162, 2002a
  7. Lee HJ, Ryu H, Park HM, Cho YK, Nahm S: Microstructural Characterizations on $({Li}_{1/2}{Pr}_{1/2})TiO_3$ Ceramics. Korean J Electron Microscopy 32(3) : 257 263, 2002b
  8. Reaney IM, Colla EL, Nava S: Dielectric and Structural Characteristics of Ba and Sr based Complex Perovskites as a Function of Tolerance Factor. Jpn J Appl Phys 33(7A) : 3984 3990, 1994 https://doi.org/10.1143/JJAP.33.3984
  9. Wakino K: Recent Development of Dielectric Resonator Materials Filter in Japan. Ferroelectrics 91 : 69, 1989 https://doi.org/10.1080/00150198908015730
  10. Woodward PM: Octahedral tilting in perovskite, I. geometrical considerations. Acta Crystallogr, Sect B B53 : 32 43, 1997 https://doi.org/10.1107/S0108768196010713