Domain imaging and local piezoelectric response of sol-gel PbTiO ₃ thin films using SPM

Ferroelectric PbTiO₃ thin films have been prepared by sol-gel route, and characterized using scanning probe microscopy. The ferroelectric domain images are obtained in the piezo- response, phase and amplitude measurements respectively, and the resultant contrast is interpreted by the induced local domain piezo-vibration. In particular, 90° and 180° domain walls appear as a transition region and a dark region in the amplitude image with a thickness of 70 nm and 8 nm, respectively. In our randomly oriented PbTiO₃ films, the local hysteresis loop measurements exhibit a variety of piezoelectric behaviors, and the additional non-switchable polarization is believed to originate from the asymmetric PbTiO₃/Pt heterostructure. Moreover, PbTiO₃ film shows an excellent polarization retention performance at the nanometer scale, which may be related to the high tetragonality of PbTiO₃ structure.