Water Quenched and Acceptor‐Doped Textured Piezoelectric Ceramics for Off‐Resonance and On‐Resonance Devices
Haoyang Leng, Yu U. Wang, Yongke Yan, Sumanta Kumar Karan, Ke Wang, Xiaotian Li, Mark A. Fanton, Joshua J. Fox, Shashank Priya
Abstract
Abstract Piezoelectric materials should simultaneously possess the soft properties (high piezoelectric coefficient, d 33 ; high voltage coefficient, g 33 ; 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), d 33 × g 33 ) and on‐resonance (FOM, Q m × k 2 ) 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% MnO 2 doped 0.19PIN‐0.445PSN‐0.365PT ceramics exhibiting giant FOM values of Q m × (227–261) along with high d 33 × g 33 (28–35 × 10 −12 m 2 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 MnO 2 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.