Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 27: Metal Oxide Surfaces I: Structure, Epitaxy and Growth

O 27.2: Vortrag

Dienstag, 2. April 2019, 10:45–11:00, H16

The surface phase diagram of strontium-lanthanum manganite in STM — •Giada Franceschi, Michele Riva, Michael Schmid, and Ulrike Diebold — Institute of Applied Physics, TU Wien, Wiedner Haupstrasse 8-10/E134, 1040, Vienna, Austria

Solid oxide fuel cells are energy conversion devices that produce clean electricity by electrochemically oxidizing a fuel. This reaction follows the incorporation of oxygen in the device via a cathode surface; the rate of this reaction is limiting the device efficiency. In most commercial applications, the cathode material is Sr-doped lanthanum manganite (La_0.8Sr_0.2MnO₃, or LSMO). Recent studies have demonstrated that the surface atomic details of a related complex oxide, SrTiO₃, are key to the oxygen incorporation [1]. To enable similar investigations on the technologically-relevant LSMO, a model for its surface structures needs to be established. To this end, we have combined pulsed laser deposition with surface techniques (most prominently STM), to grow epitaxial crystalline LSMO(110) films (10-100 nm-thick) on SrTiO₃(110). We observe a plethora of composition-related surface reconstructions that compensate for the bulk polarity. We will show our current understanding of these surface structures, along with some considerations about their stability under different oxygen chemical potentials.

[1] Riva, et al., Nat. Comm., 9, 3710 (2018)