Regensburg 2019 – scientific programme
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DS: Fachverband Dünne Schichten
DS 25: Thin Film Properties: Structure, Morphology and Composition (XRD, TEM, XPS, SIMS, RBS, AFM, ...) Part II
DS 25.3: Talk
Friday, April 5, 2019, 10:00–10:15, H32
Valence profiling of LaMnO3/SrTiO3 by use of resonant X-ray reflectometry and crystal field theory — •Michael Dettbarn1, Volodymyr B. Zabolotnyy1, Robert Green2, Michael Zapf1, Kirill Miller1, Matthias Schmitt1, Enrico Schierle3, Michael Sing1, Ralph Claessen1, and Vladimir Hinkov1 — 1Universität Würzburg and Röntgen Center for Complex Material Systems (RCCM), Würzburg — 2University of Saskatchewan, Saskatoon, Canada — 3HZB, Berlin
We have measured resonant X-ray reflectivity (RXR) and X-ray absorption spectra (XAS) on a bulk stoichiometric La7/8Sr1/8MnO3 sample and three thin LaMnO3 films of 3, 12 and 30 u.c. thickness. The manganese in the La7/8Sr1/8MnO3 sample can be modeled by a 3+ valence, whose line shape we fit theoretically by use of crystal-field theory, including a Jahn-Teller distortion.
We model the RXR spectra of the three LaMnO3 films by a mixture of Mn3+ and Mn2+ contributions, and deduce the depth profiles of the two different valencies. We compare our results with previous microscopy studies, in which a preferred occurrence of Mn2+ near the interface and surface regions was observed.