Depoling and fatigue behavior of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal at megahertz frequencies under bipolar electric field

Abstract

Bipolar electric field induced degradation in [001] poled Pb(MgNb)O-0.29PbTiO (PMN-0.29PT) single crystals was investigated at megahertz frequencies. The electromechanical coupling factor , dielectric constant , dielectric loss , and piezoelectric constant were measured as a function of amplitude, frequency, and number of cycles of the applied electric field. Our results showed that samples degrade rapidly when the field amplitude is larger than a critical value due to the onset of domain switching. We define this critical value as the effective coercive field at high frequencies, which increases drastically with frequency. We also demonstrate an effective counter-depoling method by using a dc bias, which could help the design of high field driven devices based on PMN-PT single crystals and operated at megahertz frequencies.