Structural evolution, dielectric and ferroelectric properties of (1- x )Bi 0.5 Na 0.5 TiO 3 - x Ba 0.3 Sr 0.7 TiO 3 ceramics

摘要: (1 − x)Bi0.5Na0.5TiO3−xBa0.3Sr0.7TiO3 (abbreviated as BNT-BST, x = 0.05 ~ 0.40) was prepared by a conventional ceramic processing method and their structural evolution, dielectric ferroelectric properties were investigated. The structure of the BNT-BST ceramics changes from phase coexistences Rhombohedral-Tetragonal (x ≤ 0.10) to Tetragonal-Cubic (x ≥ 0.35), across dominant Tetragonal region (0.15 ≤ x ≤ 0.30). By increasing BST content, grain size slightly decreases, while temperature Tm maximum constant gradually goes downward ~ 250 °C near room temperature. Meanwhile, with increase measuring frequency, increases for x ≥ 0.15, indicating relaxor characteristics. Room P-E loop test results show that both coercive field Ec remnant polarization Pr reduce x value ceramics. Both high peak (er > 6000 at Tm) saturated (Ps ~ 30 µC/cm2), well tunable are obtained in suitable capacitor candidate materials.