Nanoscale quantification of octahedral tilts in perovskite films

Abstract

NiO6-octahedral tilts in ultrathin LaNiO3 films were studied using position averaged convergent beam electron diffraction (PACBED) in scanning transmission electron microscopy. Both the type and magnitude of the octahedral tilts were determined by comparing PACBED experiments to frozen phonon multislice simulations. It is shown that the out-of-plane octahedral tilt of an epitaxial film under biaxial tensile stress (0.78% in-plane tensile strain) increases by similar to 20%, while the in-plane rotation decreases by similar to 80%, compared to the unstrained bulk material. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714734]