Two‐variant stripe domains in BiFeO3 films on miscut (001) SrTiO3 substrates exhibit square‐like, complete ferroelectric switching with low leakage current. Both the preferential distortion of BiFeO3 unit cells and the persistent step‐flow growth induced by the substrate anisotropy are the origins of the formation of the two‐variant stripe domains in (001) BiFeO3 films.

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This paper considers the stress distributions in bonded materials induced by differential expansion or contraction of these materials. The analytical approach is similar to the lap joint theories attributed to Volkersen and expanded by Goland and Reissner. Several simple and typical analytical models are presented to bring out the relative importance of dlrerent geometrical and material parameters and to give some insight into different modes in which the bonds might fail.

We have analyzed the ferroelastic and ferroelectric domain structure of high crystalline quality ͑001͒ BiFeO 3 films on orthorhombic ͑110͒ TbScO 3 substrates. Two domains were present in stripes separated by ͑010͒ vertical boundaries, with spontaneous polarizations in adjacent domains rotated by 109°. The striped morphology was caused by nucleation of only two ferroelastic domains on the low symmetry GdFeO 3 -type substrate. Domain engineering through substrate symmetry is an important finding for rhombohedral ferroelectric epitaxial thin films. The stripe pattern with vertical walls may be useful for extracting domain wall contributions to magnetism and electrical transport properties of BiFeO 3 materials.

Strained epitaxial SrTi0 3 films were grown on orthorhombic (I 0 I) DySC03 substrates by reactive molecular-beam epitaxy. The epitaxy of this substrate/film combination is cube on cube with a pseudocubic out-of-plane (001) orientation. The strain state and structural perfection of films with thicknesses ranging from 50 to 1000 A were examined using x-ray scattering. The critical thickness at which misfit dislocations was introduced was between 350 and 500 A. These films have the narrowest rocking curves (full width at half maximum) ever reported for any heteroepitaxial oxide film (0.001 8°). Only a modest amount of relaxation is seen in films exceeding the critical thicknesses even after postdeposition annealing at 700 °C in I atm of oxygen . The dependence of strain relaxation on crystallographic direction is attributed to the anisotropy of the substrate. These SrTi0 3 films show structural quality more typical of semiconductors such as GaAs and silicon than perovskite materials; their structural relaxation behavior also shows similarity to that of compound semiconductor films.