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 PbZr0.2Ti 0.8O3 epitaxial thin films on vicinally cut (100) oriented SrTiO3 substrate s. 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 piez o-response microscopy, we show that all a domains have their polarization a ligned along the same direction. This result is in contrast to flat substra tes where fourfold symmetry of a domains is observed. We observe that the c ritical 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 stresse s at step edges on the formation of a domains in the ferroelectric layer. ( C) 2001 American Institute of Physics.