【摘要】 利用传统陶瓷烧结方法,成功制备了巨介电常数陶瓷CaCu3Ti4O12以及Ca被Y或La取代后的Y2/3Cu3Ti4O12和La2/3Cu3Ti4O12体系.利用X射线衍射仪,测定了材料的物相结构,利用阻抗分析仪测定了不同频率和温度下材料的介电常数和介电损耗.研究结果表明,3种材料结构相似,都具有相同的类钙钛矿结构,但Y2/3Cu3Ti4O12、La2/3Cu3Ti4O12系统中具有较多的缺陷,这些缺陷是由Y和La取代Ca产生的,会对材料的介电常数产生很大的影响.体系满足极化模型,极化粒子的松弛活化过程直接与所需克服的势垒相关,而不同体系中存在的不同缺陷改变了ACu3Ti4O12体系的松弛激活能,在Y和La取代Ca后的体系中松弛激活能要远大于取代前的Ca-Cu3Ti4O12体系.更多还原

【Abstract】 CaCu₃Ti₄O₁₂ as well as Y_2/3Cu₃Ti₄O₁₂ and La_2/3Cu₃Ti₄O₁₂ was successfully prepared by traditional ceramic process.The phase structure,dielectric constant and dielectric loss were measured by X-ray diffraction spectrometer（XRD） and LCZ impedance meter,respectively.The results showed that these three materials exhibit the same perovskite-like phase structures.However,there are more defects that exist in Y_2/3Cu₃Ti₄O₁₂ and La_2/3Cu₃Ti₄O₁₂ than in CaCu₃Ti₄O₁₂,and the defects are proved to play an important role in affecting the giant dielectric constant after the element Ca is replaced by Y or La.Further analysis showed that the ACu₃Ti₄O₁₂ systems obey a model of polarization,and that the activation process of the polaron is directly related to the potential barrier.In addition,the activation energy of the polaron in different ACu₃Ti₄O₁₂ ceramics materials can be obviously altered by the defects,and therefore the activation energy in Y_2/3Cu₃Ti₄O₁₂ and La_2/3Cu₃Ti₄O₁₂ is much larger than that in CaCu₃Ti₄O₁₂ after the element Ca is replaced by Y or La.更多还原