Atomic-Scale Chemical Imaging of Composition and Bonding by Aberration-Corrected Microscopy
D. A. Muller,1,2*
L. Fitting Kourkoutis,1
M. Murfitt,3
J. H. Song,4,5
H. Y. Hwang,5,6
J. Silcox,1,2
N. Dellby,3
O. L. Krivanek3
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.
1 Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
2 Kavli Institute at Cornell, Cornell University, Ithaca, NY 14853, USA.
3 Nion Co., Kirkland, WA 98033, USA.
4 Department of Physics, Chungnam National University, Daejeon 305-764, Korea.
5 Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
6 Japan Science and Technology Agency, Kawaguchi 332-0012, Japan.
* To whom correspondence should be addressed. E-mail: dm24{at}cornell.edu
