梯度应力对BaTiO_3薄膜电性质的影响

Effect of Gradient Stress on the Dielectric Constant of BaTiO_3 Film

通过求解弹性力学方程而得到薄膜的应力分布形式,并将其用于朗道热力学理论,以解释生长于张应力衬底BaTiO3薄膜的电性质.结果表明:在生长于镀铂硅衬底的BaTiO3薄膜中,a和aa相共存,但由于两相的自发极化均平行于薄膜表面而无法观测到其电滞回线;随着温度升高,BaTiO3薄膜的等效介电常数呈现出弥散特征,其理论结果与实验结果较吻合.

A set of gradient stress was obtained by solving the elastic mechanical equations and used to Landau thermodynamic theory to explain the diffuse dielectric anomaly of BaTiO3 film grown on a tensile substrate.The results predict that a-and aa-phase may coexist in the film.The hysteretic spontaneous polarization behavior of the film can not be revealed for the in-plane polarization exists for the two phases.The temperature dependence of out-plane dielectric constant agrees with the experimental result.