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

Abstract

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, Qm ; low dielectric loss, tan δ) along with wide operation temperature (e.g., high rhombohedral-tetragonal phase transition temperature Tr-t ) for covering off-resonance (figure of merit (FOM), d33 × g33 ) and on-resonance (FOM, Qm × 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 2mol% MnO2 doped 0.19PIN-0.445PSN-0.365PT ceramics exhibiting giant FOM values of Qm × (227-261) along with high d33 × g33 (28-35 × 10-12 m2 N-1 ), low tan δ (0.3-0.39%) and high Tr-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.