Donor multiple effects on the ferroelectric and piezoelectric performance of lead-free BiFeO3-BaTiO3 ceramics

Nb-modified lead-free 0.67Bi(1.03)FeO(3)-0.33BaTi(1-x)Nb(x)O(3) ceramics were synthesized by a solid-state reaction combined with a quenching process and investigated in terms of fermelectric and piezoelectric properties. The Nb modification induced a phase change from the rhombohedral and tetragonal mixed-phase to the pseudocubic phase. This chemical modification transforms the long-range fermelectric state to a short-range relaxor fermelectric state. As a result, an excellent piezoelectric performance (d(33) = 285 pC/N and d(33)* = 403 pm/V) with high a Curie temperature, 473 degrees C and low piezoelectric strain hysteresis, 20% were achieved. Furthermore, high d(33)* at a very low field 25 kV/cm and the temperature-insensitive piezoelectric response suggest highly promising results in the lead-free BF-BT ceramics. It is believed that the high piezoelectric response is related to multiple effects such as crystal structure of morphotropic phase boundary, an optimum grain size (approximate to 5 mu m), high lattice distortion (c(T)/a(T) = 1.01) and soft-ferroelectric effect induced by the donor-doping.

Automated summary

Nb-modified lead-free BF-BT ceramics achieved excellent piezoelectric performance through chemical modification, including outstanding piezoelectric properties and relatively low piezoelectric strain hysteresis.