Synergistically enhanced strain and piezoelectric properties in BNT-modified BF–BT-based ceramic

Bismuth ferrite–barium titanate (BF–BT)-based ceramics exhibit outstanding strain and piezoelectric properties, making them crucial for various applications. However, the simultaneous enhancement of the piezoelectric coefficient and electrostrain remains challenging, and the physical mechanisms underlying property enhancement remain unclear. To realize comprehensive property optimization and deepen the understanding of the physical mechanisms in BF–BT ceramics, this study incorporates a third component, bismuth sodium titanate, into BF–BT-based ceramics. A large electrostrain (S = 0.34% @120 kV/cm) with a slightly reduced d₃₃ can be obtained in ceramics with x = 0.03, breaking the conventional tradeoff between d₃₃ and strain in relaxor ferroelectrics with nanodomains. The high d₃₃ was attributed to the rhombohedral/pseudocubic phase coexistence and the enhanced intrinsic reversible contribution. The large strain originated from the extrinsic contribution of easier domain switching, as evidenced by the enhanced polarization and ferroelectric scaling behavior.