Hysteresis Behaviors of Barium Titanate Single Crystals under Stress and Electric Field

摘要

The effects of constant bias stress on the hysteresis behaviors of (00l)-oriented barium titanate (BaTiO_3) single crystals are investigated. Large strain actuation in single crystal BaTiO_3 subjected to combined uniaxial stress and electric field is examined. A maximum strain of about 0.45% is measured under a combined loading of 2.7 MPa compressive stress and ±1.25 MVm~(-1) cyclic electric field. Domain patterns of the crystal before and after the electromechanical loading indicate that the lack of correspondence of gradients at zero electric field for the measured polarization and strain hysteresis curves is likely due to the inability of the single crystal to produce one single polarization domain at high electric fields. Multiple 90° switching systems must operate together during the unloading phase in such a way that only strain changes while polarization stays constant. Results obtained in the present study are expected to assist the development of reliable constitutive models for single crystal ferroelectrics.