Piezoelectric properties of c-axis oriented Pb(Zr,Ti)O3 thin films

Piezoelectric properties of the c-axis oriented ${\mathrm{Pb(Zr,Ti)O}}_{\mathrm{3}}$ (PZT) thin films were investigated. The PZT films with a composition near the morphotropic phase boundary were epitaxially grown on (100)Pt-coated MgO substrates by rf-magnetron sputtering. The PZT films exhibited excellent ferroelectricity with a remanent polarization more than 50 ${\mathrm{\mu C/cm}}^2$ . In order to examine intrinsic piezoelectric properties, cantilever structures were microfabricated with the PZT films. The piezoelectric coefficient $d_{31}$ of PZT films, which were not subjected to poling treatments, was measured directly from the transverse expansion of the cantilever beams. The measurements revealed that the PZT films were naturally polarized and had a relatively large piezoelectric coefficient $d_{31}$ of ${\text{100×10}}^{\text{−12}}$ m/V without poling.