Piezoelectric properties of PZT thin films on metallic substrates

Abstract

The piezoelectric properties of PZT thin films on metallic substrates prepared by sol-gel processing were investigated. The films show a high remanent polarization of about 40 μC/cm² and a coercive field strength of about 10 V/μm. The direct piezoelectric effect was used for measuring the electrical 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 μC/cm² was measured for a strain of 0.1 %. From these measurements the piezomodulus d₃₁ was calculated. The values of d₃₁ were about 29 pC/N and have been compared with former measurements of the piezomodulus d₃₃. The time dependence and the mechanical fatigue of the piezomodulus were investigated. The piezomoduli remain nearly constant up to 10⁵ mechanical or electrical cycles, after this the piezomoduli decrease.