ユーロピウム添加チタン酸バリウムセラミックスの構造と誘電特性

概要

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Eu-doped BaTiO_3 ceramics (EBT) were prepared by the cold-pressing ceramic process on the basis of the formula Ba_<1-x>Eu_xTi_<1-x/8>O_3 (x=0.01-0.05, 0.10). The effects of Eu doping on the structure, microstructure, dielectric and ferroelectric properties of BaTiO_3 ceramics were studied. EBT ceramics have a high density, a low porosity and a fine grain size of 0.7-1.0μm. As x≤3%, EBT ceramics have a tetragonal perovskite structure. The Curie point decreases linearly at a rate of -11℃/mol% Eu ions with increasing Eu content up to 0.04. However, at x≥0.04, a secondary phase, Eu_2Ti_2O_7, occurs and increases in concentration with increasing Eu, the Curie point remaining constant. The room-temperature dielectric constant of EBT ceramics (ε'_<RT>=1600-3100) shows a temperature-independent dielectric region below 50℃ at x≥0.04, a frequency stability below 10^6 Hz and good ageing resistance behavior.
2005-11-01