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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.74: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Large photoconductivity of La_0.7Ca_0.3MnO_3−δ/SrTiO₃ heterostructures — •Elke Beyreuther¹, Andreas Thiessen¹, Stefan Grafström¹, Kathrin Dörr², and Lukas M. Eng¹ — ¹Institut für Angewandte Photophysik, Technische Universität Dresden, D-01062 Dresden — ²Institut für Metallische Werkstoffe, IFW Dresden, D-01171 Dresden

The electric resistivity of stoichiometric and oxygen-deficient epitaxial 10-nm-thick La_0.7Ca_0.3MnO₃ thin films on SrTiO₃ under photoexcitation has been investigated systematically. In contrast to the as-prepared film, the oxygen-deficient one exhibits a pronounced photoinduced decrease of the resistivity of up to five orders of magnitude at low temperatures.

A detailed analysis of the resistivity as a function of illumination intensity and wavelength (visible to ultraviolet range) is presented for the bare substrate as well as for the film/substrate heterostructure. The roles of carrier generation in the film and carrier injection from the substrate, which both contribute to the observed effects, are discussed.