质量比为0.2%ZnO掺杂Ba_(0.2)Sr_(0.8)TiO_3与Ba_(0.2)Sr_(0.8)TiO_3陶瓷的结构和变温变频复介电常数的对比测量分析

Analyses of the Ceramics Structure of 0.2%ZnO Doped into Ba_(0.2)Sr_(0.8)TiO_3 Compared with Ba_(0.2)Sr_(0.8)TiO_3 and the Complex Permittivity ε* in the Condition of Scanning Temperatures and Frequencies

采用固相反应方法合成了(1-x%)Ba0.2Sr0.8TiO3+x%ZnO(x=0,0.2)陶瓷材料,并分别用X射线衍射和变温变频介电谱方法,对它们的结构和复介电常数进行了对比测量分析.结果表明,质量比为0.2%ZnO的掺杂:(1)对样品的室温晶系类型没有影响,仍然为立方晶系,晶格常数仅仅减小了0.18%;(2)弥散铁电相变的相变温度由未掺杂的136K向高温移动至140K;(3)低温铁电相的复介电常数的实部ε'减小而虚部ε"增加,高温顺电相的ε'和ε"几乎不变;(4)样品中弥散铁电相变过程的ε"与测量频率f几乎无关;(5)样品中出现在高温区的离子扩散过程向低温移动.

（1-x%）Ba02Sr0.8TiO3＋x%ZnO （x=0, 0.2） ceramics were prepared by the method of solid state reactions, and comparative measurements and analyses of their structure and complex permittivity ε＊ by X-ray diffractions and dielectric spectra of scanning temperatures and frequencies, respectively. The results show that with 0.2%ZnO doped into Bao.2Sr0.8TiO3： （1）the room-temperature crystal structure does not change, still being the cubic system, and the lattice parameter only decreases 0.18%; （2） the diffusive ferroelectric phase transition temperature shifts from 136K to 140K; （3）the real part ε＇of ε＊of the low temperature ferroelectric phase decreases while the imaginary part ε″ increases, but they change only little in the high temperature paraelectric phase; （4）it induces ε″ during the diffusive ferroelectric phase transition being independent of measuring frequency f, and （5） it also induces the high temperature ionic diffusion process shifting to low temperatures.