CaCu_3Ti_4O_(12)外延薄膜的巨介电常数特性  

Study on the Giant Dielectric Constant in CaCu_3Ti_4O_(12) Epitaxial Thin Films

作　　者：朱维婷[1] 任清褒[1] 马松华[1] 焦正宽[2] 

机构地区：[1]丽水学院物理系,丽水323000 [2]浙江大学物理系,杭州310027

出　　处：《上海交通大学学报》2007年第4期644-648,共5页Journal of Shanghai Jiaotong University

基　　金：国家自然科学基金资助项目(10274070);浙江省自然科学基金资助项目(Y606128)

摘　　要：采用脉冲激光沉积方法制备CaCu3Ti4O12薄膜，研究了其介电常数、交流电导与温度和频率的关系．实验结果表明，CaCu3Ti4O12外延薄膜的介电常数e在（1kHz，300K）时高达14700，是目前该体系最好的结果；在1kHz，100-300K温区内，ε基本保持恒定，热稳定性好、介电损耗低．该特性表明，CaCu3Ti4O12薄膜材料有可能成为信息存储器件更新换代最现实的候选材料．提出薄膜大的内应力可能是其出现巨介电常数的原因，电导与温度及频率的关系是由电子、声子与外电场的共同作用决定的．CaCu3Ti4O12 thin films were prepared by the pulsed laser deposition. The temperature and frequency dependences of the dielectric constant ε and the AC conductivity were investigated systematically. The experimental results show that the dielectric constant ε of the epitaxial CaCu3Ti4O12 thin film is as high as 14 700, at 1 kHz and 300 K, much higher than those reported recently in literature. At 1 kHz, in 100-300 K, the dielectric constant of this material almost remain unchanged and its dielectric loss is low. With these excellent properties, it is possible that CaCu3Ti4O12 thin film will become a potential candidate for information-stored devices in the future. It was proposed that the great internal stress is the reason for the giant dielectric constant. The temperature and frequency dependences of the conductivity are decided by the combined effect of electrons, phonons and external fields.

关 键 词：钙钛矿结构 脉冲激光沉积 CaCu3Ti4O12外延薄膜 介电常数 

分 类 号：O482.4[理学—固体物理]