The effect of temperature on the large field electromechanical response of relaxor ferroelectric 8/65/35 PLZT

Full hysteresis loops for the relaxor ferroelectric 8/65/35 PLZT were measured as a function of temperature. The strain–electric field hysteresis loops go from butterfly-shaped at 25 °C to a non-hysteretic quadratic electrostrictive behavior at 98 °C, while the polarization–electric field hysteresis loops go from open loops to linear as the temperature is increased. The measured strain is plotted as a function of electric displacement for each temperature, with results showing a quadratic relationship below the Curie peak with a nearly temperature-independent electrostrictive coefficient. The observed material behavior is discussed in terms of a rigid sphere model of the defect structure produced by lanthanum doping and the limitations of modeling this material behavior as a second-order phase transition are discussed.