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KMID : 0381920040340010061
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Korean Journal of Microscopy
2004 Volume.34 No. 1 p.61 ~ p.69
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Dielectric Properties and Microstructure Observation of Complex Perovskite (1-x) (Li 1/2Sm1/2 TiO3-x (Na1/2 Sm1/2)TiO3 (LNST) system [1] )
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Son Jin-Ok
Lee Hwack-Joo
Nahm Sahn
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Abstract
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The microwave dielectric properties and microstructures of the Complex Perovskite (1-x)(Li1/2Sm1/2)TiO3-x(Na1/2Sm1/2)TiO3(LNST) system were investigated using the X-ray diffraction (XRD) and scanning electron microscopy (SEM). LNST had not only the antiphase tilting of oxygen octahedron but also the inphase tilting of oxygen octahedron and the antiparallel shift of cations. Also, when 0.0땨?.4, LNST had the vacancy
ordering of A-sites because of the evaporation of Li ions. From the observation of the microstructure, abnormal grain growth phenomena were observed over the whole range of x. The temperature coefficient of resonant frequency (Tcf) of the (Li1/2?Sm1/2?)TiO3(LST) system has a large negative value (-220 ppm/℃) but the (Na1/2?Sm1/2?)TiO3(NST) system which substituted Na? has a large positive value (＋73 ppm/℃).The dielectric properties of ? = 103, Q*f0 = 3,700 GHz and Tcf =?0 ppm/�C at 4GHz were obtainedㄴ when x =0.4.
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KEYWORD
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Abnormal grain growth , Complex perovskite , Microwave dielectric properties , Temperature coefficient of resonant frequency(Tcf) , Tilting of oxygen octahedron , Vacancy ordering
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