Stress-induced depolarization of single-layer PZT 95/5 ferroelectric films

Abstract

Ferroelectric (FE) films are widely used in electronic devices and low-power FE transducers. There is significant interest in expanding the usage of FE films to ultrahigh-power systems. The results are reported herein on experimental investigations of stress-induced depolarization of single-layer PbZr0.95Ti0.05O3 doped 2% Nb (PZT 95/5) poled FE films subjected to uniaxial adiabatic compression perpendicular and antiparallel to the direction of polarization. It was found that at a stress of 2.4 GPa, the 32-μm-thick films underwent a pressure induced transition to a nonpolar antiferroelectric phase and became completely depolarized in both modes of high strain rate loading. The experimental results indicate that the behavior of stress-induced current generated by longitudinally compressed films is more complicated than under transverse stress. This complex behavior may be caused by the short stress wave transit distance through the film, that is, comparable with the thickness of the stress wave front. The important result is that the specific electric charge released by PZT 95/5 films under stress, 104 μC/cm3, is more than an order of magnitude higher than that released by bulk PZT 95/5 ceramic specimens. It was experimentally demonstrated that transversely compressed miniature PZT 95/5 film specimens with volume less than 1 cm3 are capable of producing pulses of hundreds of amperes of current. This study promises FE film applications in ultrahigh-power systems.