弛豫铁电体的键能与配位数模型  

Bond energy and coordination number model for relaxor ferroelectrics

作　　者：曹万强[1] 舒明飞[1] 

机构地区：[1]湖北大学材料科学与工程学院,武汉430062

出　　处：《物理学报》2013年第1期425-428,共4页Acta Physica Sinica

基　　金：功能材料绿色制备与应用教育部重点实验室资助的课题~~

摘　　要：基于一定浓度的杂质会在钛酸钡型铁电体中导致键能与配位数的高斯型分布原理,利用键能与配位数起伏模型导出了介电峰温与测量频率的关系.当键能和配位数的相对起伏接近时,其关系呈现出一般弛豫铁电体所普遍具有的Vogel-Fulcher函数形式,且冻结温度仅与键能的相对起伏和激活能有关.并由此解释了低掺杂浓度下杂质均匀分布导致弥散性的机理和超过临界浓度时的弛豫铁电性的机理.同时提出,杂质替代对畴的形成和生长所产生的强烈抑制作用及微畴化是实现键能起伏与配位数起伏一致的来源.Based on the gaussian-type distributions of bond energy and coordination number for barium titanate systematic ferroelectrics doping with a certain quantity of dopants, the bond energy and coordination number fluctuation model is used to derive the relationship between peak of dielectric constant and testing frequency. The universal Vogel-Fulcher function of the relationship is demonstrated, when the fluctuations of bond energy and coordination number approach to each other. The frozen temperature of the Vogel-Fulcher function is related only to actuation energy and relative fluctuation of bond energy. The mechanisms of dispersion due to homogenous distribution of dopants in low doping concentration and relaxor due to gaussian-type distribution of dopants over a critical concentration are investigated. It is suggested that strong inhibitory effect of substituted ions on formation and growth of ferroelectric domain is the main source of bond energy fluctuation and coordination number fluctuation.

关 键 词：弛豫铁电性 介电弥散 键能 配位数 

分 类 号：TM277[一般工业技术—材料科学与工程]