Mg掺杂BaTiO_3介电陶瓷中氧空位缺陷的EPR监控

EPR Monitoring of Oxygen-vacancy Defects in Mg-doped BaTio_3 Dielectric Ceramics

在烧结温度Ts=1 400℃下,采用固相反应法制备(Ba1-xMgx)TiO_3(x=0.015)和Ba(Ti1-xMgx)O3(x=0.015)陶瓷.以电子顺磁共振(EPR)技术作为关键技术,研究了陶瓷的点缺陷.结果表明:BMT为六方和伪立方钛酸钡结构的混合相,BTM为六方和四方钙钛矿结构的混合相.在低于-100℃的菱方相中,探测到与氧空位相关g=1.956的EPR信号,且Ba空位、Ti空位和O空位共存.

(Ba_(1-x)Mg_x) TiO_3 and Ba( Ti1-xMgx)O3-x( x = 0.015) ceramics were prepared by the solid-state reaction method at a sintering temperature of Ts = 1 400 ℃. Electron paramagnetic resonance( EPR) was employed as a key technique to study the point defects of ceramics. The results show that BMT ceramic exhibited the mixed phases of hexagonal and pseudo cubic perovskite structures,BTM ceramic exhibited the mixed phases of hexagonal and tetragonal perovskite structures.An EPR signal at g = 1.956,which is associated with oxygen-vacancy defects,was detected in the rhombohedral phase below T =-100 ℃. Three types of point defects of Ba,Ti,O vacancies could coexist in ceramics.