Effects of doping Bi and Nd on the phase transition and electric properties of (Bi1/2Na1/2)0.94Ba0.06TiO3 ceramics

Abstract

(Bi1/2Na1/2)0.94Ba0.06TiO3 (BNBT6) ceramics with 3 wt.% Bi2O3 and xwt.%Nd2O3 (x = 0, 1.5, 4.5, 6.0) doping were prepared by solid state reaction. The phase transition behaviors and electric properties of ceramics were investigated. The results showed that with doping of 3 wt.% Bi2O3, an antiferroelectric (AFE) phase was induced in ferroelectric BNBT6 ceramics at room temperature. It was attributed to disruption of the ferroelectric coupling between [BO6] octahedra since the generation of A-site vacancies. The AFE (Bi1/2Na1/2)0.94Ba0.06TiO3-3wt.%Bi2O3 (BNBT6-3B) ceramics showed a high phase transition temperature (Tm ~ 320 °C), corresponding to the AFE - paraelectric (PE) phase transition. Low Nd2O3 (x = 1.5, 4.5) doping was helpful to strengthen the AFE phase of BNBT6-3B, while high Nd2O3 (x = 6.0) resulted in a stronger frequency dispersion due to the enhancement of A-site cation disorder. With increasing temperature, the ceramics with low Nd2O3 underwent a relaxor AFE - AFE - PE phase transition, while only relaxor AFE - PE phase transition was presented in high Nd2O3-doped ceramics. An excellent dielectric properties (emax = 2916) was obtained in x = 1.5 sample.