Jump to main content
Jump to site search

Issue 3, 2014
Previous Article Next Article

Revealing the atomic structure and strontium distribution in nanometer-thick La0.8Sr0.2CoO3−δ grown on (001)-oriented SrTiO3

Author affiliations

Abstract

Surface segregation in metal oxides can greatly influence the oxygen transport and surface oxygen exchange kinetics critical to the performance of solid-state devices such as oxygen permeation membranes and solid oxide fuel/electrolytic cell electrodes. Unfortunately detecting elemental distributions at the atomic scale near the surface remains challenging, which hampers the understanding of underpinning mechanisms and control of surface segregation for the design of high-performance materials. Using the coherent Bragg rod analysis (COBRA) method, we report the first direct 3D atomic imaging of a 4 nm-thick “La0.8Sr0.2CoO3–δ”/SrTiO3 epitaxial film. Of significance, energy differential COBRA revealed pronounced Sr segregation (La1−xSrxCoO3−δ, x ∼ 0.4) in the four unit cells from the top surface while complete Sr depletion was detected in the five unit cells from the “La0.8Sr0.2CoO3−δ”/SrTiO3 interface. The drastic strontium compositional changes in the film were associated with large changes in the atomic positions of apical oxygen sites in the perovskite structure. Such Sr segregation tendencies toward the surface were also found in nominal “La0.6Sr0.4CoO3−δ” thin films, which can greatly enhance the surface oxygen exchange properties of oxides. The results presented here show that COBRA and the differential COBRA methods can be used to investigate a variety of electrochemically active systems providing atomic scale structural and chemical information that can help understand the physical and chemical properties of these systems and serve as a basis for comparison with DFT calculations.

Graphical abstract: Revealing the atomic structure and strontium distribution in nanometer-thick La0.8Sr0.2CoO3−δ grown on (001)-oriented SrTiO3

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 21 Sep 2013, accepted on 03 Jan 2014 and first published on 06 Jan 2014


Article type: Paper
DOI: 10.1039/C3EE43164A
Citation: Energy Environ. Sci., 2014,7, 1166-1174
  •   Request permissions

    Revealing the atomic structure and strontium distribution in nanometer-thick La0.8Sr0.2CoO3−δ grown on (001)-oriented SrTiO3

    Z. Feng, Y. Yacoby, W. T. Hong, H. Zhou, M. D. Biegalski, H. M. Christen and Y. Shao-Horn, Energy Environ. Sci., 2014, 7, 1166
    DOI: 10.1039/C3EE43164A

Search articles by author