Ce_<0.9>Sm_<0.1>O_<2-δ>における酸化物イオン伝導と誘電率の関係

概要

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The relationship between electrical conductivity and dielectric constant was investigated for 10 atom %Sm doped CeO_2 (Ce_<0.9>Sm_<0.1>O_<2-δ>), which is a typical oxide-ion conductor. Computer simulation clarified that anomalously large dielectric constant originated from the superimposition of both Debye-type dipole and inter facial polarization between electrolyte and electrode. The interfacial polarization was proportional to the inverse of the frequency, suggesting the accumulation of oxide ions at the inter facial sites with high-energy barriers due to the oxide-ion conduction. Ac conductivity (σ_<ac>) at high temperatures and high frequencies agreed with the σ_<ac> value, but lowered in such a frequency region that the Debye-type polarization appeared. The activation energy for σ_<ac> agreed with those for Debye-type polarization and inter facial polarization, suggesting that these thermal exciting processes originate from oxide-ion diffusion.
社団法人日本セラミックス協会の論文
2007-01-01