Effect of poling conditions on out-of-plane displacement for a shear mode PZT actuator

A shear mode plate-shaped lead zirconate titanate (PZT) actuator for a novel actuating module in a microdroplet ejecting system was fabricated and tested. A novel poling design with both poling electrodes on the same surface is proposed. The actuator is made with lateral polarization parallel to the plane, in contrast to the conventional actuator with the polarization along the plate-thickness direction. Due to the requirement for the excellent electromechanical coupling characteristics, the samples poled under various poling conditions were tested and compared to determine the optimum conditions. The poling conditions, including the poling voltage, poling temperature and poling duration, affect the electromechanical characteristic or output actuated displacement. The distribution of electric field in the sample during poling was simulated using commercial finite element method (FEM) software to predict the appropriate poling voltage. Experimental results indicate that the optimum conditions are a poling voltage of 7 kV, a poling temperature of 120 °C and a poling duration of 10 min. The sample with the optimum condition has the highest out-of-plane displacement of 400 nm under an actuating peak-to-peak voltage of 120 Vpp.