Uniaxial compressive stress dependence of the high-field dielectric and piezoelectric performance of soft PZT piezoceramics

The influence of uniaxial prestress on dielectric and piezoelectric performance was studied for soft lead zirconate titanate piezoceramics. High electric field induced polarization and longitudinal/transverse strain were measured at different compression preload levels of up to -400 MPa. The parameters evaluated included polarization/strain outputs, dielectric permittivity, piezoelectric constants, and dissipation energy as a function of the mechanical preload and electric-field strength. The results indicate a significant enhancement of the dielectric and piezoelectric performance within a certain prestress loading range. At much higher stress levels, the predominant mechanical depolarization effect makes the material exhibit hardly any piezoeffect. However, the enhanced performance achieved by a small stress preload is accompanied by an unfavorable increased hysteresis, and consequently, increased energy loss, which is attributed to a larger extrinsic contribution due to more non-180degrees domain switching induced by the combined electromechanical load.