Bi_2O_3掺杂Ba_(0.2)Sr_(0.8)TiO_3+4%ZnO陶瓷的介电弛豫特性研究  

Study on Dielectric Relaxation Properties of Ba_(0.2)Sr_(0.8)TiO_3+4% ZnO Ceramics Doped by Bi_2O_3

作　　者：张惠珍[1] 赵兴宇[1,2] 丁捷[1] 杜卫平[1] 尹红梅[1,2] 

机构地区：[1]伊犁师范学院物理科学与技术学院新疆凝聚态相变与微结构实验室,新疆伊宁835000 [2]南京大学物理学院国家固体微结构重点实验室,江苏南京210093

出　　处：《伊犁师范学院学报（自然科学版）》2013年第3期54-56,62,共4页Journal of Yili Normal University：Natural Science Edition

基　　金：新疆科技支疆项目(201091112);中国科学院"西部之光"人才培养计划(RCPY 200906);国家973子项目(2012CB821503)

摘　　要：本文合成了Ba0.2Sr0.8TiO3+4%ZnO+xBi2O3(x=2%,2.5%,3%)系列陶瓷,并在频率1Hz^105Hz、温度100K^450K、升温速率为1K/min的条件下,测量了介电谱.对于所有的组分,实部'的曲线上,在100K^200K之间都出现了一个P1峰,同时在300K^450K之间实部'和虚部''曲线上也都出现了一个P2峰,且P1、P2的峰温随频率的增加都向高温移动.随着Bi2O3掺杂量的增加,可以观察到实部'上的P1峰和虚部''上的P2峰先往低温移动,再往高温移动.在x=3.0%的组分中,介电常数虚部''上还在240K附近出现了一个明显的P3峰,峰温随着频率f的增大往高温移动.利用Arrhenius关系拟合得到了各组分的P1和P2弛豫过程,以及x=3.0%组分的P3弛豫过程的激活能E与0.结果表明,P1和P2过程的E的值都偏大,0的值过小,表明它们都是多体耦合的弛豫过程.P1的结果可能是受Ba0.2Sr0.8TiO3+4%ZnO中弥散相变过程的影响,材料并未完全形成为弛豫铁电体而导致的;P3过程的E和0的值符合常见弛豫过程的取值范围.A series of Ba0.2Sr0.8TiO3＋4%ZnO＋xBi203 （x=2%, 2.5%, 3%） ceramics are prepared, and their complex dielectric constant is measured in frequency range of 1Hz-10SHz and temperature range of 100K-450K with heating rate of IK/min. For all components, there are a Pl peak of real part ε′ between 100K to 200K and a P2peak of imaginary part ε″ between 300 to 450K. The peak temperatures of P1 and P2 move towards high temperatures with increasing frequency. Both the P1 and P2 peak shift to low temperature first and then to high temperature with increasing doping content of Bi2O3. Moreover, there is a P3 peak of imaginary part ε″ near 240K for the ceramic of x=3%, and its peak temperatures move towards the high temperature with increasing frequency. The activation energy E and τ0 of P1, P2 and P3 processes are gained by fits with the Arrhenius relation. The results show that the E values of P1 and P2 are too large while τ0 values are too small, which shows that P1 and P2 are relaxation processes of multi-body coupling. The result of P1 may be caused by diffused phase transition process of Ba0.2Sr0.8TiO3＋4%ZnO. The E and ro value of P3 are in reasonable range of individual relaxation processes.

关 键 词：介电弛豫 弛豫铁电体 钛酸锶钡 

分 类 号：O469[理学—凝聚态物理]