Unit cell orientation of tetragonal-like BiFeO3 thin films grown on highly miscut LaAlO3 substrates

Synchrotron and lab-scale x-ray diffraction shows that tetragonal-like T′-BiFeO3 films on miscut LaAlO3 substrates (α < 5°) exhibit (00l)-planes tilted away from those of the substrate as predicted by the “Nagai model” (except for miscut < 0.2°). Tilts as large as 1° are achieved even in 100 nm thick films, strikingly larger than those observed in other perovskites. We attribute this to the large c/a ratio and the high crystalline coherency of the T′-BiFeO3/LaAlO3 interface. This coherency is possible through an observed “diagonal-on-diagonal” film/substrate alignment. Interestingly, the substrate miscut does not influence the relative population of monoclinic domains.