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| Hauptseite > Publikationsdatenbank > Tuning the physical properties of La0.7Sr0.3MnO3-δ via oxygen off-stoichiometry using thermal annealing |
| Hauptseite > Publikationsdatenbank > Tuning the physical properties of La0.7Sr0.3MnO3-δ via oxygen off-stoichiometry using thermal annealing |
| Poster (Invited) | FZJ-2023-01283 |
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2023
Abstract: The oxygen off-stoichiometry in La0.7Sr0.3MnO3-δ (LSMO) thin films on SrTiO3 (STO) substrates has been investigated employing Al-assisted vacuum annealing. The gradual deoxygenation during annealing induces a topotactic phase transition from the as-prepared Perovskite (PV, ABO3) phase to a layered oxygen-vacancy-ordered Brownmillerite (BM, ABO2.5) phase. The structural change is monitored by XRD. A metal-to-insulator and simultaneously a ferromagnetic (FM)-to-antiferromagnetic (AF) transition is found. The variation of the manganese oxidation state is characterized using XAS. The BM phase shows in magnetization vs. temperature curves a peculiar peak above room temperature which cannot be explained within the usual AF ordering at low temperatures. Moreover, to elucidate the role of the strain to the substrate, bulk-like LSMO powder samples were prepared and annealed at similar conditions as the film samples. Also here the PV-BM phase transition is achieved.
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