Piezoelectric and ferroelectric properties of lead-free LiNbO₃-modified 0.97(Bi_0.5Na_0.5TiO₃)-0.03BaZrO₃ ceramics

Lead-free piezoelectric ceramics (1−x) [(0.97Bi_0.5Na_0.5TiO₃)]-0.03BaZrO₃-xLiNbO₃ (BNT-BZ3-xLN) with x = (0–0.07) were synthesized using the conventional solid-state reaction method, and their crystal structure, microstructure, and dielectric, ferroelectric and piezoelectric properties were investigated as a function of the LN content. The X-ray diffraction patterns revealed the formation of a single-phase perovskite structure for all the LN-modified BNT-BZ ceramics in this study. The results indicate that the LN substitution into BNT-BZ3 induces a transition from a ferroelectric to a diffuse and/or relaxor state accompanying a field-induced strain of 0.20% for x = 0.05 at an applied field of 6 kV/mm. The corresponding dynamic piezoelectric coefficient for this composition was (S_max/E_max = 333 pm/V). A significant reduction of the coercive field (E_c) and enhancement of the piezoelectric constant (d₃₃) from 98 pC/N for x = 0 to 117 pC/N x = 0.01 was observed.