Grain orientation dependent superelasticity in ferroelectrics for enhanced electromechanical properties

The practical application of ferroelectric ceramics is limited by their inherent electromechanical property constraints. Superelasticity, characterized by considerable recoverable strain and piezoelectric coefficient in ferroelectrics, offers a promising solution for advanced actuators and sensors. However, the complex electromechanical coupling effects caused by different oriented grains pose challenges for implementing superelasticity in ferroelectric ceramics. This paper elucidates that superelasticity is prominently exhibited within small orientation regimes but becomes suppressed as the orientation increases. Grain orientation affects electromechanical properties: Young's modulus abruptly drops from 91 to 3 GPa near the superelastic transition at the orientation angle of 0°, while it stabilizes around the intrinsic modulus at 45°. The peak piezoelectric coefficient reaches 5000 pC/N near the transition at 0°, exceeding the previously reported values by an order of magnitude. The proposed grain orientation-centered mechanism of superelasticity offers valuable theoretical support for designing ferroelectric devices with grain distributions, particularly in textured ceramics.