Near-ideal electromechanical coupling in textured piezoelectric ceramics

Abstract

Abstract Electromechanical coupling factor, k , of piezoelectric materials determines the conversion efficiency of mechanical to electrical energy or electrical to mechanical energy. Here, we provide an fundamental approach to design piezoelectric materials that provide near-ideal magnitude of k , via exploiting the electrocrystalline anisotropy through fabrication of grain-oriented or textured ceramics. Coupled phase field simulation and experimental investigation on <001> textured Pb(Mg 1/3 Nb 2/3 )O 3 -Pb(Zr,Ti)O 3 ceramics illustrate that k can reach same magnitude as that for a single crystal, far beyond the average value of traditional ceramics. To provide atomistic-scale understanding of our approach, we employ a theoretical model to determine the physical origin of k in perovskite ferroelectrics and find that strong covalent bonding between B-site cation and oxygen via d - p hybridization contributes most towards the magnitude of k . This demonstration of near-ideal k value in textured ceramics will have tremendous impact on design of ultra-wide bandwidth, high efficiency, high power density, and high stability piezoelectric devices.