Dielectric hysteresis from transverse electric fields in lead zirconate titanate thin films

Excellent symmetric dielectric hysteresis is observed from lead zirconate titanate (PZT) thin films using transverse electric fields driven by interdigitated surface electrodes. The 1-mu m-thick PZT films with a Zr/Ti ratio of 52/48 are prepared on ZrO2 buffered, 4-in.-diam silicon wafers with a thermally grown SiO2 layer. Both the ZrO2 buffer layer and PZT film are deposited by using a similar sol-gel processing. Remanent polarization of about 20 mu C/cm(2) with coercive field less than 40 kV/cm is obtained as measured using a triangle wave at 50 Hz. Thicker films are being developed and retention for the transversely polarized state is currently under study. One of the objectives of this study is to develop a large array of d(33)-driven unimorph sensing elements for a high-resolution acoustic imaging system. (C) 1999 American Institute of Physics. [S0003-6951(99)03123-X].