不同A位元素(La、Y、Ca)的ACu_3Ti_4O_(12)陶瓷介电性能研究  

Dielectric behaviors of ACu_3Ti_4O_(12) with Ca,La and Y elements at A site of perovskite phase structure

作　　者：周小莉[1] 杜丕一[1] 韩高荣[1] 翁文剑[1] 

机构地区：[1]浙江大学硅材料国家重点实验室

出　　处：《浙江大学学报（工学版）》2006年第8期1446-1449,1476,共5页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(50372057;50332030);浙江省科技计划重点资助项目(2005C21119)

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.CaCu3 Ti4 O12 as well as Y2/3 Cu3 Ti4 O12 and La2/3 Cu3 Ti4 O12 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 Y2/aCuaTi4 O12 and La2/3 CuaTi4 O12 than in CaCuaTi4 O12, 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 ACu3Ti4012 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 ACu3Ti4 O12 ceramics materials can be obviously altered by the defects, and therefore the activation energy in Y2/3Cu3Ti4O12 and La2/3Cu3Ti4O12 is much larger than that in CaCu3Ti4O12 after the element Ca is replaced by Y or La.

关 键 词：A位替换 CACU3TI4O12 LaCu3Ti4O12 介电性能 

分 类 号：TB34[一般工业技术—材料科学与工程]