Atomic structure of Ba0.5Sr0.5TiO3 thin films on LaAlO3

Abstract

Perovskite barium strontium titanate Ba0.5Sr0.5TiO3(BST) thin films were grown on (001) LaAlO3 (LAO) using pulsed-laser ablation. The microstructures of the as-grown BST films were studied with selected electron diffraction, transmission electron microscopy, and scanning transmission electron microscopy. The BST thin films are oriented with their [001] directions parallel to the 〈102〉 directions of the LAO. Both cross-sectional and plan-view studies show the BST films to be single crystals with smooth surfaces. The interfaces were seen to be atomically sharp by cross-sectional, high-resolution electron microscopy. The density of misfit dislocations was consistent with the 4.3% lattice mismatch, and they were found to be dissociated into partials.