Recovery of piezoelectric properties after low temperature heat treatment for AC poled Pb(Mg1/3Nb2/3)O₃-0.295PbTiO₃ single crystal

The thermal stability of AC-polarised (ACP) Pb(Mg₁/₃Nb₂/₃)O₃-0.295PbTiO₃ (PMN-PT) single crystals with a [001] orientation was investigated at temperatures ranging from room temperature to 100 °C. At 25°C, the ACP specimen exhibited a dielectric constant of 8900, a piezoelectric coefficient d ₃₃ of 2670 pC/N and a transverse piezoelectric coefficient of -d₃₁ of -1060 pC/N. Following heat treatment at 100 °C, followed by cooling to room temperature, these values decreased to 2650, 680 pC/N and -400 pC/N, respectively. However, applying DC poling to this sample restored properties close to their initial values: a dielectric constant of 9400, a d ₃₃ value of 2950 pC/N and a - d ₃₁ value of -1080 pC/N. These values surpassed the initial ACP properties, confirming the recovery of ACP characteristics. These results suggest that the domains in ACP PMN-PT single crystals remain stable even above the phase transition temperature (Trt), offering significant advantages for practical applications.