Characterization of transverse piezoelectric properties of c-axis oriented PbTiO3 thin films

In this study, we evaluated transverse piezoelectric properties of c -axis oriented PbTiO3 (PT) thin films from the actuation of the PT/MgO unimorphs. The PT films were grown on Pt/MgO substrates using rf-sputtering technique. X-ray diffraction measurements revealed that the PT films exhibited highly c -axis orientation with a -axis domains, suggesting epitaxial growth of the PT films. The piezoelectric characteristics of the PT films were estimated by the measurements of tip deflection of the unimorph cantilevers composed of PT films and MgO substrates. The PT cantilevers showed excellent linear piezoelectric deflection even with the application of large reverse voltage to the polar direction. The stable piezoelectricity of the PT films is attributed to not only large coercive field larger than their break down field but the highly c -axis orientation of PT films. We estimated piezoelectric coefficient e(31) of the PT thin films and obtained large transverse piezoelectricity of e(31) = - 1.77 C/m(2) which is two times larger than that of the PT single crystals.