Structure and dielectric properties of composition graded K(Ta, Nb)O3 crystals

Hisanori Yamane, Koichiro Morita, Masahiko Shimada

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    1 Citation (Scopus)

    Abstract

    K(Ta, Nb)O3 crystals having a composition gradient were prepared by non-equilibrium cooling from melts of K(TaxNb1-x)O3 with x=0.3-0.7. Electron microprobe analysis revealed that the Ta content was rich in the core region of the crystals and decreased gradually to the edge with increasing Nb content. Zoning structures were observed in the crystals by polarized optical microscopy and high-temperature microscopy. There were three zones (cubic, tetragonal and orthorhombic phases from the core to the rim) or two zones (tetragonal (core) and orthorhombic phases (rim)). The boundary between the cubic and tetragonal zones moved to the edge with increasing temperature. The crystals exhibited broad peaks for the dielectric constant against temperature. No frequency dependence of the peak position was recognized from 100 kHz to 10 MHz.

    Original languageEnglish
    Pages (from-to)1051-1054
    Number of pages4
    JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
    Volume62
    Issue number11
    DOIs
    Publication statusPublished - 1998

    Keywords

    • Dielectric constant
    • Functionally graded materials
    • Perovskite-type structure
    • Phase transition

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Mechanics of Materials
    • Metals and Alloys
    • Materials Chemistry

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