Ultra-thin PbTiO3 films : thickness and ferroelectricity

The ferroelectric properties of epitaxial PbTiO3 thin films with thickness < 15 nm have been studied. The films were grown on SrTiO3 (001) substrates with SrRuO3 bottom electrodes using pulsed laser deposition. Growth was monitored down to the deposition of individual monolayers using reflection high-energy electron diffraction. Piezoresponse force microscopy was used to study the ferroelectric response of the perovskites thin films. Using film thicknesses ranging from 5.9 to 14.6 nm PbTiO3 it was found that the thin films show a clear ferroelectric response down to 9.0 nm.