La掺杂对Sr_2Bi_4Ti_5O_(18)铁电陶瓷性能的影响  

Effect of La doping on the properties of Sr_2Bi_4Ti_5O_(18) ferroelectric ceramics

作　　者：卢网平[1] 朱骏[1] 惠荣[1] 陆文峰[1] 陈小兵[1] 

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002

出　　处：《功能材料》2003年第5期562-563,566,共3页Journal of Functional Materials

基　　金：江苏省教育厅自然科学基金资助项目(01KJB140011)

摘　　要：　利用传统的固相烧结工艺制备了Sr2LaxBi4-xTi5O18(x=0.00、0.05、0.1、0.25、0.5、0.75、1.00)陶瓷样品。用X射线衍射对其微结构进行了分析,并测量了其铁电、介电性能。X射线衍射结果表明La掺杂对Sr2Bi4Ti5O18的晶体结构几乎没有影响。样品的铁电、介电结果表明,随着La掺杂量的增加,样品的剩余极化(2Pr)和矫顽场(Ec)逐渐减小,这是由于离子半径较大的La取代类钙钛矿层A位Bi离子,使得样品晶格畸变变小,从而导致2Pr降低,晶格畸变的减小也使得沿着外电场方向氧八面体中的阳离子更易运动,导致Ec减小。样品的相变温度Tc随着La含量的增加而降低,这也与样品晶格畸变有关。Sr2Bi4-xLaxTi5O18 (SBLTix) ferroelectric ceramic samples of which x=0, 0.05, 0.1, 0.25, 0.5, 0.75, 1.0 were prepared by traditional solidstate reaction method. Their microstructure was analyzed by Xray diffraction. The result shows that pure Sr2Bi4Ti5O18 phase is formed. From the results of ferroelectric and dielectric measurements, the Sr2Bi4Ti5O18 remnant polarization (2Pr) and coercive field (Ec) are 22.4μC·cm-2 and 46kV·cm-1 respectively, and Curie temperature (Tc) was 309℃. It was found that with the increasing of lanthanum content, the remnant polarization, coercive field and Curie temperature decreased. These results can be explained as follows: in the SBLTi system, the substitution larger ion radius La for Asite Bi atoms in the pseudoperovskite blocks, leads to less structural distortion, resulting in smaller 2Pr and lower Tc, and also lead to an easy motion of the octahedral cations.

关 键 词：Sr2Bi4Ti5O18 铁电陶瓷 铁电性能 氧空位 晶格畸变 相变温度 掺杂 

分 类 号：TM22[一般工业技术—材料科学与工程]