Ferroelectric PZT thin films on metallic substrates: preparation and properties as actor and sensor element

Electromechanical properties of PZT thin films on metallic substrates have been investigated for different substrate geometries. The PZT thin films with high single layer thicknesses of about 0,9 μm have been prepared by modified sol-gel processing. The films show a high remanent polarization of about 30 μC/cm² and strains up to 0.4%, the piezoelectric modulus was 60 pC/N and the dielectric permittivity of about 400. By applying a voltage below the coercivity of a poled sample 50 mm in length, the deflection of the sample tip can be controlled linearly between ±0.3 μm. In the first mechanical resonance mode the vibration of the sample tip can be observed by the naked eye. The dependence of the mechanical resonance frequencies on the cantilever dimensions is in a good agreement with the mechanical bending theory. The charge generated by a quasistatic mechanically bending of the bimorph was investigated as a function of the average curvature