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In this article, we examine the initial polarization of PbTiO3 thin films grown epitaxially on SrRuO3 electrodes. It is found that the as-grown predominant polarization is directed toward the SrRuO3 bottom electrode in films thinner than 20 nm and directed toward the top surface in thicker films. The data is interpreted in terms of a Landau–Ginzburg–Devonshire model for a semiconducting ferroelectric with asymmetric boundary conditions. Based on the measured hysteresis loops and the stability of the two polarization directions with time, it is concluded that charged defects serve to impose a preferential downward polarization in very thin films. [ABSTRACT FROM AUTHOR]

The crystalline and dielectric properties of sputter deposited PbTiO3 thin films were investigated as a function of the film thickness and growth temperature. The crystalline quality was found to be independent of the film thickness from 2.4 to 200 nm. The capacitance of 0.12 mm2 Pt/PbTiO3/SrRuO3 and Pt/PbTiO3/Nb:SrTiO3 capacitors was found to deviate from the ideal parallel plate capacitance for PbTiO3 films thinner than 10 nm. The decrease in capacitance was consistent with field penetration into the electrodes. The surface Pb content, as determined from x-ray photoelectron spectroscopy, was found to decrease with increasing growth temperature from 700 to 760 °C. However, no change could be observed in the crystalline quality. [ABSTRACT FROM AUTHOR]