Optimized piezoelectric properties and temperature stability in PSN‐PMN‐PT by adjusting the phase structure and grain size

For relaxor ferroelectric materials, improving the piezoelectric properties and temperature stability simultaneously is still a great challenge up to now. In this work, the structure, electric properties, and thermal stability of xPSN‐(1 − x)PMN‐0.4PT (x = 0.15, 0.29, 0.43, and 0.5) ceramics were studied systematically by experiment and phase field simulation. A high Curie temperature Tc of 255℃ and good longitudinal electricmechanical coupling factor k33 of 0.75 and piezoelectric constant d33 of 650 pC/N are achieved in x = 0.43 ceramics with monoclinic C and tetragonal phases coexistence at room temperature. At 30℃, this composition ceramics sintered at 1260℃ shows the remnant polarization Pr and coercive field Ec are about 36.8 µC/cm2 and 8.2 kV/cm respectively. Moreover, as the temperature increases to 150℃, these values remain as high as 22.6 µC/cm2 and 5.7 kV/cm. In the temperature range of 30–230℃, the variation of k33 and d33 is about 24% and 25%. These high piezoelectric performance and superior temperature stability are related to the more complex domain structures caused by phase coexistence and larger grains with more stable domain structure due to internal stress. The former is beneficial in improving the piezoelectric properties, and the latter dominates the enhanced temperature stability.