フェーズフィールド法による酸素空孔を有する非分極・分極チタン酸バリウム多結晶の圧電・誘電特性評価

抄録

This paper studies the dielectric and piezoelectric behavior of unpoled and poled barium titanate (BaTiO₃) polycrystals with oxygen vacancies. A phase field model is employed for BaTiO₃ polycrystals, coupled with the time-dependent Ginzburg-Landau theory and the oxygen vacancies diffusion, to demonstrate the interaction between oxygen vacancies and domain evolutions. To generate grain structures, the phase field model for grain growth is also used. The hysteresis loop and butterfly curve are predicted at room and high temperatures. The permittivity, and longitudinal and transverse piezoelectric constants of the BaTiO₃ polycrystals are then examined for various grain sizes and oxygen vacancy densities.