Ferroelectric Characteristics of Pb-containing Perovskite-Pyrochlore Composites

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J. Korean Ceram. Soc. > Volume 34(5); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(5): 500.

Pb계 Perovskite-Pyrochlore 복합체의 강유전특성

조진우, 손정호¹, 조상희

경북대학교 무기재료공학과
¹가야대학교 전자세라믹공학과

Ferroelectric Characteristics of Pb-containing Perovskite-Pyrochlore Composites

ABSTRACT

Perovskite Pb0.7Ba0.3Zn1/3Nb2/3O3 substituted with 0.3 mole fraction for Pb-site in PbZn1/3Nb2/3O3 relaxor and pyrochlore Pb1.83Ba0.29Zn1.71Nb2/3O6.39 were mixed and dielectric characteristics of this composites were investigated. Percolation limit of perovskite phase, which was determined by microstructural observation in the composite as an isolation of perovskite phase from pyrochlore matrix, was 28.9-47.5 vol%. Ferroelectric phase transition below percolation limit depends on a parameter which affects the propagation of lattice vibration between isolated perovskite phase and pyrochlore matrix. Therefore, it is believed that ferroelectric lattice vibration of isolated perovskite phase could be transfered to pyrochlore matrix when the oxygen octahedra are linked in 3-dimension and highly polarizable Pb2+ ions are contained in both phases.

Key words: Ferroelectrics, Composites, Cooperative dielectric interaction, Percolation limit, Dielectric properties, Lattice vibration