Berlin 2012 – scientific programme

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DS: Fachverband Dünne Schichten

DS 28: Thin film characterization: structure analysis and composition (Spectroscopy)

DS 28.1: Talk

Wednesday, March 28, 2012, 17:45–18:00, H 2032

X-ray absorption and resonant photoelectron spectroscopy of epitaxial Fe-doped SrTiO₃ — •Annemarie Köhl¹, Christian Lenser¹, Dariusz Kajewski², Jurek Kubacki², Chencheng Xu¹, Sebastian Wicklein¹, Jacek Szade², and Regina Dittmann¹ — ¹Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Germany — ²A.Chelkowski Institute of Physics, University of Silesia, Katowic, Poland

In recent years resistive switching in transition metal oxides received a lot of research interest due to the proposed application as non-volatile data memory. SrTiO₃ serves as a model system for the investigation of resistive switching due to the valency change mechanism. Frequently, slightly Fe doping is used, as it has shown to improve the switching properties. The focus of this study is the effect of Fe-doping of SrTiO₃ in thin epitaxial films.

Thin film samples with Fe concentration of 2 at.% and 5 at.% were prepared by pulsed laser deposition at varying substrate temperatures. The surface morphology of the films is studied with AFM. X-ray absorption spectroscopy is performed in total-electron and auger-electron yield offering different probing depths. Significant variations of the Fe-L edge between bulk and interface as well as after annealing are observed and discussed in terms of integration into the lattice and evolution of secondary phases. Resonant photoelectron spectroscopy at the absorption edge of Ti, O and Fe was used to determine the spectral contributions to the valence band. Most noteworthy we find significant spectral weight above the valence band, which can be attributed to Fe-states.