Thermally induced phase switching in mechanically biased single crystal relaxors

In this work, we examine the time-dependent piezoelectric response of [011] poled rhombohedral [Pb(In_1/2Nb_1/2)O₃]_0.24[Pb(Mg_1/3Nb_2/3)O₃]_0.44[PbTiO₃]_0.32 single crystals under variable thermal loading. We find that thermal radiation incident on a piezoelectric crystal held under mechanical compressive bias stress generates an abrupt jump in strain with a rise time <1 ms, much faster than the bulk thermal time scale. This discontinuity is associated with a weak first-order ferroelectric-ferroelectric structural phase transition as confirmed by in situ X-ray diffraction results. We demonstrate that this transition can be cycled repeatedly with low thermal hysteresis (<3 °C) under zero applied electric field with a sizable reversible strain jump of ∼0.12%. Moreover, we show that the thermally driven phase switching behavior can be tuned by varying the bias stress and/or electric field, establishing effective control parameters and conditions for future applications such as actuators, thermally controlled transducers, and sensors.