Effects of sintering temperature and Bi2O3, Y2O3 and MgO co-doping on the dielectric properties of X8R BaTiO3-based ceramics

Abstract

Bi 2 O 3 , Y 2 O 3 and MgO co-doped BaTiO 3 (BT)-based X8R ceramics were synthesized successfully for the first time. The effects of the sintering temperature and Bi 2 O 3 , Y 2 O 3 and MgO dopants on the dielectric properties were investigated systematically. Bi 2 O 3 doping can increase the Curie temperature ( T c ), but reduces the overall dielectric permittivity. On the other hand, Y 2 O 3 doping is beneficial to the formation of core-shell microstructure and the increase of T c , whereas MgO can prevent excessive Y 2 O 3 from diffusing into grain core, and thereby further contributes to the generation of the core–shell microstructure. The generation of the typical core-shell microstructure was confirmed and investigated in detail by using transmission electron microscopy (TEM). It is argued that the synergistic effects of Bi 2 O 3 , Y 2 O 3 and MgO co-doping in terms of the formation of the core-shell structure and the increase of T c , can help improve the temperature stability of the dielectric permittivity effectively. Increasing the sintering temperature leads to an increase in the grain size, which in turn leads to an increase in the overall dielectric permittivity due to the grain size effect.