Effect of uniaxial stress on the electromechanical response of 〈001〉-oriented Pb (Mg13 Nb23) O3 -PbTi O3 crystals

The 〈001〉-oriented 0.7PMN-0.3PT and 0.67PMN-0.33PT crystals are characterized under uniaxial stress and electric field loading above the coercive field. Strain-electric-field and electric-displacement-electric-field hysteresis loops are measured at various compressive stresses showing a notable effect of stress on the electromechanical coupling. A moderate uniaxial stress can advance their electromechanical properties. Stress-strain curves are run at zero electric field, showing that depolarization for 〈001〉-oriented 0.7PMN-0.3PT crystal begins at 7 MPa, while as little as 3 MPa for 0.67PMN-0.33PT crystal, placing a severe limitation in actuator applications.