Abstract
The surface states of the perovskite-type cerium-, thorium- and strontium-doped lanthanum cobalt oxides (La1−xCexCoO3), La1−xThxCoO3, La1−xSrxCoO3x = 0 to 0.03) have been investigated using X-ray photoelectron spectroscopy (XPS). The binding energy differences (ΔBE) between Co2p3/2 and 01s of lattice oxygen have a maximum value atx = 0.02 in both La1−xCexCoO3 and La1−xThxCoO3. From this result, it is expected that the bonding state between the surface cobalt and lattice oxygen is mostly ionic at this point. The valence band (VB) spectra change greatly atx = 0.02 in both cerium- and thorium-doped samples. We speculate that the high spin trivalent cobalt ion is dominant atx = 0.02 on the surface. On the other hand, the ABEs between Co2p3/2 and 01s of lattice oxygen decrease with increasingx in La1−xSrxCoO3. It is expected that the bonding states become covalent in proportion tox. The change of the VB spectra for La1−xSrxCoO3 near the Fermi level (EF) can be explained by the formation of the impurity level.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
