Structure and electrical properties of PMN-PZT micro-actuator deposited by tape-casting process

A potential application for Pb(Mg1/3Nb2/3)O3-Pb(Zr0.52T{i}0.48)O3 (PMN-PZT) piezoelectric material is micro positioning and actuation for hard disk drives. And this material was developed and the processing of a piezoelectric multilayer element for stacking and co-firing Ag/Pd electroded tape casting layers was investigated. The formation mechanisms of PMN-PZT ternary solid solution prepared by the mixed oxides techniques has been characterized by differential thermal analysis (DTA) and thermal gravimetric analysis (TGA). The sintered microstructure and composition of the PMN-PZT multilayer elements were investigated by scanning electron microscope (SEM), and X-ray spectrometer (EDX). The data from DTA/TGA stress the importance of a slow debonding from room temperature to 500 ∘C. The joining of the electrode to the PMN-PZT layer confirms that the internal electrodes are well defined and is well interconnected to the PMN-PZT layer. The ferroelectric polarization-electric (P-E) hysteresis loops of the piezoelectric films were also measured. The remanent polarization and coercive field calculated from the P-E curves decreased with decreasing the number of PMN-PZT multilayer films from 10-layer to 4-layer. After that, a novel U-type micro-actuator attached to each side via piezoelectric elements was also practically measured by laser Doppler vibrometer in order to testify the driving mechanics of it. The highest displacement/voltage sensitivity of 1.496 μm/±20 V is achieved by the micro-actuator with two 10-layer elements. The corresponding resonance frequency of the sway mode is high at 12 kHz.