Control of domain structure of epitaxial PbZr0.2Ti0.8O3 thin films grown on vicinal (001) SrTiO3 substrates

We have investigated the polydomain formation in 100-200-nm-thick PbZr0.2Ti0.8O3 epitaxial thin films on vicinally cut (100) oriented SrTiO3 substrates. Our results show that there is a preferential location of the nucleation of the a domains along the step edges of the underlying substrate. By piezo-response microscopy, we show that all a domains have their polarization aligned along the same direction. This result is in contrast to flat substrates where fourfold symmetry of a domains is observed. We observe that the critical thickness for a domain formation is much lower than that for PbZr0.2Ti0.8O3 films grown on flat substrates. We have developed a model based on minimization of elastic energy to describe the effect of localized stresses at step edges on the formation of a domains in the ferroelectric layer. (C) 2001 American Institute of Physics.