Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 52: Magnetic Thin Films II

MA 52.7: Vortrag

Freitag, 20. März 2015, 11:15–11:30, H 1012

Charge Carrier Doping in Electrolyte-Gated Mesostructured La_1−xCa_xMnO₃ and La_1−xSr_xMnO₃ Thin Films with Cubic Pore Symmetry — •Christian Reitz, Philipp Moritz Leufke, Horst Hahn, and Torsten Brezesinski — Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

Here, we report on the preparation of mesostructured perovskite-type thin films of La_1−xSr_xMnO₃ (LSMO) and La_1−xCa_xMnO₃ (LCMO) from common sol-gel precursors by taking advantage of the superior templating properties of polyisobutylene-block-poly(ethylene oxide) diblock copolymers. We show that the overall sample preparation process is straightforward and both oxides are well defined in terms of structure and morphology after calcination, with complex percolation pathways for electron transport. We also show that the charge carrier density in electrolyte-gated LSMO and LCMO thin films can be modulated electrostatically to a large extent. This kind of doping allows for reversible ”tuning” of the magnetization. Charge induced modulations of up to 5% at 300 K and 9% at 230 K can be achieved for LSMO and LCMO, respectively. These values are the highest thus far reported for electrolyte-gated mixed-valence manganese oxides with perovskite-type structure, thus emphasizing the benefits of nanoscale porosity. Overall, we will focus on the unique magnetic and magnetotransport properties as well as on the surface charge induced magnetization changes in polymer-templated LSMO and LCMO thin films with nanocrystalline walls.