Control of domain structure of epitaxial PbZr_0.2Ti_0.8O₃ thin films grown on vicinal (001) SrTiO₃ substrates

We have investigated the polydomain formation in 100–200-nm-thick PbZr_0.2Ti_0.8O₃ 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 PbZr_0.2Ti_0.8O₃ 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. © 2001 American Institute of Physics.