BST薄膜的复阻抗谱及其电导性能的研究

Impedance spectroscopy of BST thin films and their electrical conductitity

应用Sol-Gel工艺制备了BST薄膜 .应用复阻抗谱和模量谱技术研究了BST薄膜的介电响应 ,实验结果表明 :BST薄膜的阻抗谱曲线是一个完整的半圆 ,且阻抗谱半圆存在压低现象 ,而与此对应 ,复阻抗和复模量的频谱曲线只存在一个峰值 ,表明BST薄膜的介电响应主要起源于样品的晶粒体行为 ,而晶粒边界以及电极与薄膜界面的贡献可以忽略 .交直流电导分析结果表明 ,BST薄膜的交直流电导激活能分别为 93.5kJ mol和 1 0 0 .3kJ mol。

Barium strontium titanate(BST) thin films were prepared by sol-gel method.The dielectric response of BST thin films were studied as a function of frequency and ambient temperature(from roon temperature to 500?℃) by employing impedance and modulus spectroscopy.The experimental show that the impedance spectroscopy of BST thin films were well-defined semicircles with the center below the real axis.The impedance and modulus spectroscopy plots appeared only one peak,it was show that the major response was due to the grain,while contributions from the grain boundary or the electrode/film interface was negligible.The value of the activation energies computed from the Arrhenius plots of both ac and dc conductivities with 1000/T 93.5?kJ/mol and 100.3?kJ/mol,respectively.The values revealed that the degradation of BST thin films was attributed to the motion of oxygen vacancies within the bulk.