Water Quenched and Acceptor-Doped Textured Piezoelectric Ceramics for Off-Resonance and On-Resonance Devices

Piezoelectric materials should simultaneously possess the soft properties (high piezoelectric coefficient, d₃₃; high voltage coefficient, g₃₃; high electromechanical coupling factor, k) and hard properties (high mechanical quality factor, Q_m; low dielectric loss, tan δ) along with wide operation temperature (e.g., high rhombohedral–tetragonal phase transition temperature T_r–t) for covering off-resonance (figure of merit (FOM), d₃₃ × g₃₃) and on-resonance (FOM, Q_m × k²) applications. However, achieving hard and soft piezoelectric properties simultaneously along with high transition temperature is quite challenging since these properties are inversely related to each other. Here, through a synergistic design strategy of combining composition/phase selection, crystallographic texturing, defect engineering, and water quenching technique, <001> textured 2 mol% MnO₂ doped 0.19PIN-0.445PSN-0.365PT ceramics exhibiting giant FOM values of Q_m × (Formula presented.) (227–261) along with high d₃₃ × g₃₃ (28–35 × 10⁻¹² m² N⁻¹), low tan δ (0.3–0.39%) and high T_r–t of 140–190 °C, which is far beyond the performance of the state-of-the-art piezoelectric materials, are fabricated. Further, a novel water quenching (WQ) room temperature poling technique, which results in enhanced piezoelectricity of textured MnO₂ doped PIN-PSN-PT ceramics, is reported. Based upon the experiments and phase-field modeling, the enhanced piezoelectricity is explained in terms of the quenching-induced rhombohedral phase formation. These findings will have tremendous impact on development of high performance off-resonance and on-resonance piezoelectric devices with high stability.