Piezoelectric properties of PZT thin films on metallic substrates

The piezoelectric properties of PZT thin films on metallic substrates prepa red by sol-gel processing were investigated. The films show a high remanent polarization of about 40 mu C/cm(2) and a coercive field strength of about 10 V/mu m. The direct piezoelectric effect was used for measuring the elec trical charge generated by an applied strain. The generated charge depends linearly on the strain up to a strain of about 0.1 %. A charge per area of about 0.1 mu C/cm(2) was measured for a strain of 0.1 %. From these measure ments the piezomodulus d(31) was calculated. The values of d(31) were about 29 pC/N and have been compared with former measurements of the piezomodulu s d(33). The time dependence and the mechanical fatigue of the piezomodulus were investigated. The piezomoduli remain nearly constant up to 10(5) mech anical or electrical cycles, after this the piezomoduli decrease.