Regensburg 2019 – scientific programme

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.33: Poster

Tuesday, April 2, 2019, 17:00–20:00, Poster E

Surface dead layer in thin manganite films studied by Surface-Enhanced Raman Spectroscopy — Sebastian Merten, •Jonas Wawra, and Vasily Moshnyaga — I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

Half-metallic mixed-valence manganites are promising materials for spintronic applications. However, extrinsic effects, like surface dead layer or chemical segregation, prevent that they unfold their true potential. Here, we present a Surface-Enhanced Raman (SER) spectroscopy study of the surface dead layer in doped La_0.7(Ca or Sr)_0.3MnO₃ thin films, grown by MAD technique. The required Au nanoparticles have been grown with the same technique. The SER spectra of the free manganite surface reveal an electron-enrichment, manifested by the appearance of strong Jahn-Teller stretching modes. To manipulate this electron-rich surface layer, we have modified the manganite surface by deposition of 1-2 monolayers of SrO, MgO and TiO₂, and compared the obtained SER spectra with those from the free surface. Financial support of the Deutsche Forschungsgesellschaft via SFB TP A02 is acknowledged.