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Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: Thin Film Applications

DS 6.5: Talk

Monday, March 12, 2018, 16:00–16:15, H 0111

The Influence of Crystallographic Order on Ferrimagnetic Response of Spinel ZnFe2O4 Thin Films — •Vitaly Zviagin, Yogesh Kumar, Chris Sturm, Israel Lorite, Pablo Esquinazi, Marius Grundmann, and Rüdiger Schmidt-Grund — Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Linnéstr. 5, Leipzig

We present the dielectric function of normal spinel ZnFe2O4 (ZFO) grown at different pressures and temperatures on SrTiO3 (100) substrate by pulsed laser deposition. Electronic transitions visible in the diagonal element of the dielectric tensor are assigned to transitions involving Fe2+, Fe3+ and Zn2+ cation 3d and 4s orbitals. Transitions from O2p to tetrahedrally coordinated Fe3+ cation, located at ∼ 3.5 eV, and between octahedrally coordinated Fe2+ cations, located at ∼ 0.9 eV, give evidence to disorder in the normal spinel structure. Growth temperature dependent investigation has shown a direct correlation between saturation magnetization at 5 K and the amplitude of the former mentioned transition, likely due to the dominant nature of the oxygen mediated coupling between Fe3+ located on two different lattice sites.[1] Annealing films at temperatures greater than 250 C in argon and oxygen atmospheres facilitates a decrease in the ferrimagnetic response and is explained by reordering of the disordered spinel structure toward ordered normal state. A direct correlation between the disorder cation transition contributions to the dielectric function and room temperature ferrimagnetic response is shown.
V. Zviagin et al., Appl. Phys. Lett. 108, 13 (2016)

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