Atomic-scale chemical imaging of composition and bonding by aberration-corrected microscopy

Using a fifth- order aberration- corrected scanning transmission electron microscope, which provides a factor of 100 increase in signal over an uncorrected instrument, we demonstrated two- dimensional elemental and valence- sensitive imaging at atomic resolution by means of electron energy- loss spectroscopy, with acquisition times of well under a minute ( for a 4096- pixel image). Applying this method to the study of a La0.7Sr0.3MnO3/SrTiO3 multilayer, we found an asymmetry between the chemical intermixing on the manganese- titanium and lanthanum- strontium sublattices. The measured changes in the titanium bonding as the local environment changed allowed us to distinguish chemical interdiffusion from imaging artifacts.