Lu在BaTiO_3陶瓷中的位占据研究

Dielectric Properties and Site Occupation of Lu in BaTiO_3 Ceramics

采用冷压陶瓷技术分别制备名义分子式为(Ba1-xLux)Ti1-x/4O3、Ba(Ti1-xLux)O3-x/2、(Ba1-xLux)(Ti1-xLux)O3(x=0.01,0.02)的陶瓷.由X射线衍射(XRD)、扫描电镜(SEM)、介电温谱(DTC)和电子顺磁共振(EPR)技术调查Lu在BaTiO3陶瓷中的位占据.结果表明:仅仅在(Ba1-xLux)Ti1-x/4O3陶瓷中存在单相四方钙钛矿结构,且固溶度为x=0.01;其他5个陶瓷的主钙钛矿相内均有少量第二相Lu2O3或Lu2Ti2O7析出.在具有细晶粒微结构的单相(Ba1-xLux)Ti1-x/4O3(x=0.01)陶瓷中,Lu3+离子占据Ba位,诱致Ti空位缺陷;但占据Ba位的Lu3+离子不能完全填充本征的Ba空位,导致Ba空位和Ti空位缺陷共存.

The cold-pressing ceramic technique was used to prepare nominal（ Ba1- xLux） Ti1- x /4O3、Ba（ Ti1- x Lux） O3- x /2、（ Ba1- xLux）（ Ti1- xLux） O3（ x = 0. 01,0. 02） ceramics. The site occupation of Lu in BaTiO3 ceramics was investigated using X-ray diffraction（ XRD）,scanning electron microscopy（ SEM）,dielectrictemperature characteristics（ DTC）,and electron paramagnetic resonance（ EPR） techniques. The results indicated that only a single-phase tetragonal perovskite structure existed in（ Ba1- xLux） Ti1- x /4O3 ceramics and the solid solution limit is x = 0. 01. A small amount of secondary phases Lu2O3 or Lu2Ti2O7separated out in the main perovskite phase of the other five ceramics. For the single-phase（ Ba1- xLux） Ti1- x /4O3（ x = 0. 01）ceramic with a fine-grained microstructure,Lu3 ＋ions occupied Ba sites and induced Ti-vacancy defects.However,Lu3 ＋ions occupying Ba sites could not fill in intrinsic Ba vacancies completely,leading to coexistence of Ba-vacancy and Ti-vacancy defects.