Dielectric Properties of ZnO-doped <TEX>$Pb(Mg_{1/3} Nb_{2/3}) O_3-PbTiO_3$</TEX> Ceramics

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J. Korean Ceram. Soc. > Volume 33(10); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(10): 1117.

ZnO첨가된 $Pb(Mg_{1/3} Nb_{2/3}) O_3-PbTiO_3$ 세라믹의 유전특성

김월명, 변재동¹, 김효태², 김윤호²

고려대학교 공과대학 재료공학과
¹고려대학 공과대학 재료공학과
²한국과학기술연구원 세라믹스 연구부

Dielectric Properties of ZnO-doped $Pb(Mg_{1/3} Nb_{2/3}) O_3-PbTiO_3$ Ceramics

ABSTRACT

Microstructure and dielectric properties of ZnO-doped (1-8 mol%) 95P(Mg1/3 Nb2/3) O3+5PbTiO3(95PMN+5PT) ceramics were investigated. From SEM analysis it was found that second phases were observed in all the specimens doped with ZnO and the amount of second phases increased with ZnO content. Pb Mg, Nb Ti and Zn were detected in the second phase by EDS. Lattice parameter and diffuseness parameter increased with ZnO content and Tmax(temperature at which dielectric constant is maximum) shifted to higher temperature with ZnO content. These experimental results indicate that some of Zn2- added were incorporated in amorphous phase and the rest substituted Mg2+ Substitution of Zn2- for Mg2- is thought to enhance the formation of microdomain(Mg/Nb=1) of short-range order and this colud be explained by the fact that ionic size difference between Zn2+ and Nb5+ is larger than that between Mg2+ and Nb5- The highest dielectric contric constant was achieved in specimen with 2 mol% ZnO content sintered at 90$0^{circ}C$ for 2 hours. The specimen thous prepared had a resistivity of2$times$1011 $Omega$.cm

Key words: $Pb(Mg_{1/3} Nb_{2/3}) O_3-PbTiO_3$, Zinc oxide, Dielectric properties