【摘要】 利用Landau-Ginzburg-Devonshire(LGD)热力学唯象理论计算了BaTiO3自发极化强度和有效介电常数与其粒径的关系,在1~1 000nm范围内分别进行对数理论(Lich)、有效介质理论(MGT)、有效介质理论(EMT)和Jayasundere-Smith(J-S)修正理论拟合,得到了不同粒径下钛酸钡/环氧树脂(BaTiO3/Epoxy)复合材料的有效介电常数。研究表明,BaTiO3单一组分时,在粒径约300nm处有较高的室温有效介电常数;与Epoxy复合后,在BaTiO3体积分数较低(10%~40%)时由J-S理论计算的结果与实验值吻合良好。更多还原

【Abstract】 The relationship between the spontaneous polarization strength and effective dielectric constant of BaTiO3 and its grain-size has been calculated based on landau-ginzburg-devonshire(LGD)phenomenological theory in this paper.Lich,MGT,EMT and J-S theoretical equations were used to simulate the effective dielectric constants of BaTiO3 /Epoxy composite in the range of 1nm to 1000nm.The results show that the single component specimen of BaTiO3 with grain size of 300nm has a high effective dielectric constant at room temperature,and J-S equation could be well fitted to the experimental data at low volume fraction(10%~40%)when it was composited with Epoxy.更多还原