Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 86: Oxide Semiconductors for Device and Energy Applications 2
HL 86.5: Vortrag
Donnerstag, 10. März 2016, 16:00–16:15, H11
Optical and Magneto-Optical Investigation of Normal and Disordered ZnFe2O4 in Relation to Magnetic Properties — •Vitaly Zviagin1, Peter Richter2, Yogesh Kumar1, Israel Lorite1, Michael Lorenz1, Dietrich R.T. Zahn2, Georgeta Salvan2, Pablo Esquinazi1, Marius Grundmann1, and Rüdiger Schmidt-Grund1 — 1Universtät Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, Germany — 2Technische Universtät Chemnitz, Semiconductor Physics, Reichenheiner Str. 70, Germany
We present the magneto-optical dielectric tensor of normal and disordered ZnFe2O4 grown at different temperatures on MgO (100) and SrTiO3 (100) substrates by pulsed laser deposition. Optical transitions in the diagonal element of the dielectric function, obtained by spectroscopic ellipsometry, are identified as transitions from O2p to Fe3+ 3d and 4s bands. Via the off-diagonal element, obtained by magneto-optical Kerr effect spectroscopy, the observed features are confirmed to be similar to the mentioned transitions. One transition in particular, namely a transition from O2p to tetrahedrally coordinated Fe3+ cation, located at ∼ 3.5 eV, suggests disorder of the normal crystal structure. Its amplitude is highest for the sample grown at the lowest temperature in both the diagonal and off-diagonal elements of the dielectric tensor. Furthermore, the overall magnetic response, measured by SQUID, is highest for the sample grown at the lowest temperature, suggesting that the presence of Fe3+ on the tetrahedral sites is directly related to the ferrimagnetic order of the crystal due to the dominating nature of the oxygen mediated coupling between the two lattice sites.