K(Ta,Nb)O3 single crystals having a composition gradient were prepared by non-equilibrium cooling from melts of K(TaxNb1-x)O3 with x=0.3-0.4. 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.
|ジャーナル||Key Engineering Materials|
|出版ステータス||Published - 2001 1 1|
|イベント||7th Conference and Exhibition of the European Ceramic Society - Brugge, Belgium|
継続期間: 2001 9 9 → 2001 9 13
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