Dielectric, ferroelectric and field-induced strain response of lead-free BaZrO3-modified Bi0.5Na0.5TiO3 ceramics

Lead-free piezoelectric ceramics (1 − x)Bi0.5Na0.5TiO3–xBaZrO3 (BNT–BZ100x, with x = 0–0.10) were prepared using a conventional solid-state reaction method. The crystal structure, microstructure, dielectric, ferroelectric, and piezoelectric properties of BNT–BZ100x ceramics were studied as functions of different BZ content. X-ray diffraction patterns revealed that the BZ completely diffused in the BNT lattice in the studied composition range. An appropriate amount of BZ addition improved the dielectric, ferroelectric, and piezoelectric properties of BNT ceramics. The remanent polarization (Pr) and piezoelectric constant (d33) increased from 22 μC/cm2 and 60 pC/N for pure BNT to 30 μC/cm2 and 112 pC/N for x = 0.040, respectively. In addition, electric field-induced strain was enhanced to its maximum value (Smax = 0.40%) with normalized strain (d*33 = Smax/Emax = 500 pm/V) at an applied electric field of 8 kV/mm for x = 0.055. The enhanced strain can be attributed to the coexistence of ferroelectric and relaxor ferroelectric phases.