Dielectric Properties of Nanocrystalline TiO_(2) Prepared by the Stearic Acid Gel Method

Nanocrystalline TiO 2 was prepared by means of a stearic acid gel method. The product was investigated by differential thermal analysis, thermogravimetric analysis, X-ray powder diffraction and transmission electronic microscopy(TEM). The results of the dielectric properties tested indicate that the dielectric constant of anatase-form nanocrystalline TiO 2 is much higher than that of the coarse crystal. The dielectric constant of the nanocrystalline material is not related with the amplitude of an external AC field in a certain range.

纳米金红石相TiO_2块体的介电特性研究

在大气和真空条件下 ,对纳米金红石相TiO2 块体进行介电频谱测试。发现样品在大气中的相对介电常数比其在真空中的数值高 10 2 ～ 10 3 倍 ;大气中介电损耗高于其在真空中的数值 ,大气中频率约在 3kHz时出现损耗最小值 ,真空中介电损耗则随频率增加而单调减小。分析认为纳米金红石相TiO2 介电常数异常是由材料界面中的缺陷和悬键所引起的。在大气中 ,纳米金红石TiO2 的介电损耗以极化损耗 (电偶极矩转向极化和离子弛豫极化 )为主 ,而在真空中则以电导损耗为主。