Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 19: POSTER Ia

MA 19.60: Poster

Dienstag, 17. März 2015, 09:30–13:00, Poster A

Control of stoichiometry in LaMnO₃/La₂MnO₄ thin films grown by pulsed laser deposition — •Arun Singh Chouhan^1,2, Supratik Dasgupta¹, Vikas Shabadi¹, Aldin Radetinac¹, Philipp Komissinskiy¹, Ajay D Thakur², and Lambert Alff¹ — ¹Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt — ²Department of Physics, Indian Institute of Technology Patna, India

Growth of perovskites (ABO₃) by pulsed laser deposition (PLD) requires a simultaneous precise control of multiple process parameters. In particular, the interplay between laser fluence, growth atmosphere, and pressure affects the stoichiometry and, thereby, also the physical properties of compounds such as LaMnO₃ where the B-site cation is known to have multiple stable oxidation states. Although stoichiometric bulk LaMnO₃ is an A-type antiferromagnetic insulator, several independent studies have reported a ferromagnetic order in thin films, attributed to an off-stoichiometry driven double exchange interaction between the mixed Mn³⁺ and Mn⁴⁺ oxidative states. In spite of repeated efforts, as grown thin films with magnetic saturation below ∼0.4 µ_B/f.u. have so far not been reported. Here, we present a systematic growth study with a fine control of cation stoichiometry and oxidation state, allowing to stabilize LaMnO₃ (with Mn³⁺) and La₂MnO₄ (with Mn²⁺) from the same target by choosing the appropriate deposition conditions.