Effect of Sn2+ Ion Substitution on Dielectric Properties of (Ba,Ca)TiO3 Ferroelectric Ceramics

概要

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In this study, we investigated the sintering atmosphere dependence of the electric properties of Sn-doped (Ba0.82Ca0.13)TiO3 ceramics to clarify the effect of Sn2+ ions. The temperature of the dielectric constant peak for Sn-doped (Ba0.82Ca0.13)TiO3 ceramics sintered in a low $P$(O2) ($1\times 10^{-11}$ MPa) atmosphere is higher than that for the sample sintered in a high $P$(O2) ($2\times 10^{-2}$ MPa) atmosphere. The remanent polarization and coercive field for the Sn-doped (Ba0.82Ca0.13)TiO3 ceramics sintered at low $P$(O2) ($1\times 10^{-11}$ MPa) also increased compared with those of the sample sintered at high $P$(O2) ($2\times 10^{-2}$ MPa) at room temperature. The low $P$(O2) sintering atmosphere for Sn-doped (Ba0.82Ca0.13)TiO3 ceramics leads to a high tetragonality and the existence of Sn2+ ions. In addition, by X-ray absorption spectroscopy, it was verified that Sn2+ ions occupy Ba2+ sites in the (Ba0.82Ca0.13)TiO3 ceramics. Consequently, it is concluded that the high ferroelectric-to-paraelectric phase transition temperature and the high remanent polarization on the ceramics originate from Sn2+ ions substituted for Ba2+ sites in Sn-doped (Ba0.82Ca0.13)TiO3 ceramics.
2010-09-25