Comparison of structural, ferroelectric, and piezoelectric properties between A-site and B-site acceptor doped 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 lead-free piezoceramics.

The effects of A-site Li- or B-site Fe-doping into 0.93(Bi 0.5 Na 0.5)TiO 3 -0.07BaTiO 3 (BNBT) ceramics were systematically investigated for the compositional ranges of (Bi 0.465 Na 0.465 Ba 0.07) 1- x Li x TiO 3 (BNBT- x Li) and (Bi 0.465 Na 0.465 Ba 0.07)Fe x Ti 1- x O 3 (BNBT- x Fe) (x = 0.01–0.03). The R3c / P4bm phase ratio remained essentially unchanged across the entire set of Li and Fe doping levels studied. Although some typical characteristics for acceptor doping were observed for both BNBT- x Li and BNBT- x Fe, their ferroelectric and piezoelectric properties were different. A clear transition from a slim (BNBT, E c = 17.0 kV/cm, P r = 22.9 μC/cm2) to square-like P-E hysteresis loops (E c = 29.9 kV/cm, P r = 33.9 μC/cm2) was observed in BNBT- x Li at x ≥0.02. In contrast, constricted P-E loops (E c = 13.0–15.7 kV/cm and P r = 28.6–31.7 μC/cm2) and deformed butterfly S-E curves were detected in all BNBT- x Fe ceramics. These results suggest A-site Li doping as a more effective method for stabilizing the non-ergodic relaxor phase in BNT-BT ceramics, which could help further tailor the piezoelectric properties in other A-site doped Bi-based perovskite systems. [ABSTRACT FROM AUTHOR]