 |
Journal articles
Crystal field effects on the photoemission spectra in Cr2O3 thin films: from multiplet splitting features to the local structure
Abstract : Changes in the shape of X-ray photoemission (XPS) spectra can be related to changes in the local structure of a transi-tion metal. By combining Crystal Field Multiplet calculations and well-controlled molecular beam epitaxy growth of alpha-Cr2O3(0001) thin films on alpha-Al2O3(0001) substrates, we prove that it possible to link the features of Cr 2p XPS spectra with local distortions of CrO6 octahedra and d-orbitals reorganization. Hence, we show that the splitting of the Cr 2p3/2 envelope is related to the degeneracy of the t2g orbital triplet, which corresponds to a fully relaxed structure. Conversely, the broad unstructured Cr 2p3/2 envelope relies on splitting of t2g orbitals and it is the fingerprint of large trigonal distor-tions of CrO6 octahedra. Then, using the Cr 2p XPS as a structural tool for -Cr2O3, we show that the Cr2O3 protective layer formed by oxidation of polycrystalline Ni30Cr alloy exhibits in-plane strains at early oxidation stages and grows preferentially along the c-axis.
https://hal-cea.archives-ouvertes.fr/cea-03265613
Contributor : Contributeur Map Cea <>
Submitted on : Monday, June 21, 2021 - 9:58:23 AM
Last modification on : Tuesday, July 13, 2021 - 3:27:34 AM
Contributor : Contributeur Map Cea <>
Submitted on : Monday, June 21, 2021 - 9:58:23 AM
Last modification on : Tuesday, July 13, 2021 - 3:27:34 AM