Enhanced piezoelectric strain of BiFeO ₃ –Ba(Zr _0.02 Ti _0.98 )O ₃ lead‐free ceramics near the phase boundary

Abstract The x BiFeO ₃ ‐(1‐ x )Ba(Zr _0.02 Ti _0.98 )O ₃ + 1.0 mol% MnO ₂ ( x BF‐BZT) lead‐free piezoelectric ceramics were prepared by conventional solid‐state reaction method. The structure, dielectric, and piezoelectric properties were studied. X‐ray diffraction (XRD) analysis showed that x BF‐BZT ceramics exhibited pure perovskite structure with the coexistence of tetragonal and rhombohedral phases (0.66 ≤ x ≤ 0.74). The Curie temperature T _c , the dielectric constant ε _r (1 kHz), dielectric loss tan δ (1 kHz), piezoelectric constant d ₃₃ , coercive field E _c (80 kV/cm), and remnant polarization P _r (80 kV/cm) of 0.7BF‐0.3BZT‐Mn ceramics were 491°C, 633, 0.044, 165 pC/N, 35.6 kV/cm, and 22.6 μC/cm ² , respectively. The unipolar strain of 0.7BF‐0.3BZT reached up to 0.20% under the electric field of 60 kV/cm, which is larger than that (0.15%) of BiFeO ₃ –BaTiO ₃ ceramics. These results indicated that the x BF‐BZT ceramics were promising candidates for high‐temperature piezoelectric materials.