Abstract text (incl. figure legends and references)

Perovskite oxides have a wide range of tuneable physical properties and are of interest for electronic and energy-related applications. In superlattices of Pr_0.7Ca_0.3MnO₃/SrRuO₃ (PCMO/SRO), the anomalous Hall effect depends sensitively on the crystal structures of the SrRuO₃ layers, while the field dependence of the Hall resistivity is related to the PCMO layer thickness. Here, we use integrated differential phase contrast (iDPC) scanning transmission electron microscopy (STEM) to study the influence of layer thickness on the structures of PCMO/SRO superlattices. As high angle annular dark field (HAADF) images have poor sensitivity to light elements such as oxygen, especially in close proximity to heavy elements, we use iDPC imaging for the simultaneous visualisation of oxygen and metal atoms in real space. We determine atomic positions with sub-pixel precision and measure atomic tilt angles quantitatively. We use simulation results to establish an approximately linear relationship between optimal defocus and sample thickness in SRO, which provides a guide for tuning the defocus experimentally during iDPC STEM experiments. Our results show that atomic tilt angles in the SRO layers depend on the thicknesses of the PCMO layers, with thicker PCMO layers resulting in smaller oxygen tilt angles and different magnetic properties.