摘要
制备CaCu3Ti4O12陶瓷,在50 K^300 K温区范围内测试试样介电性能。研究结果表明,CaCu3Ti4O12结晶完整性、晶界及缺陷对其巨介电常数的大小、出现低介电常数向高介电常数转变时对应温度的高低以及对极化粒子的温度活化响应弥散程度有直接的影响。随晶界和缺陷的下降,极化粒子受缺陷相互作用相应减弱,产生松弛时需要克服的势垒下降,对应的产生松弛的温度随之降低。材料的结晶越完整,极化粒子的温度活化响应弥散现象越小,由低到高介电常数的转变速度越快。
Giant dielectric properties of CaCu3Ti4O12 ceramic disc, prepared by .solid reaction,were studied in a temperature ranging from 50 K to 300 K. Its surface microstructures were characterized with scanning electron microscopy （SEM） .The results show that various factors, such as the crystallinity of CaCu2Ti4O12 grains, grain boundaries, defects and pores, significantly affect the dielectric properties of the ceramic to a varying degree, including the relative maximum dielectric constant, the critical temperature of low-high dielectric constant transition as well as the temperature dependence of polarized ion relaxation. As the densities of grain boundary and defect reduce, the relaxation temperature of the polarized ion drops down because interaction of defects and polarized ions weakens, decreasing the relaxation potential barrier. We suggest that the better the grain crystallinity, the weaker the temperature dependence of relaxation and the faster the low-high dielectric constant transition.
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2006年第1期40-42,47,共4页
Chinese Journal of Vacuum Science and Technology
基金
浙江省科技计划(第一批)重点项目(No.2005C21119)
