Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 16: Layer Properties: Electrical, Optical, and Mechanical

DS 16.3: Vortrag

Dienstag, 8. März 2016, 10:00–10:15, H11

The Effect of Layer Thickness on the Magnetic and Magneto-optical Properties of Sputtered and Annealed La_1−xSr_xMnO₃ Thin Films on Silicon — •Manuel Monecke, Oana-Tereza Ciubotariu, Peter Richter, Patrick Thoma, Georgeta Salvan, and Dietrich R.T. Zahn — Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz, Germany

La_1−xSr_xMnO₃ (LSMO) is a conductive oxide with a perovskite crystal structure. Moreover, the high spin polarization makes this material an ideal electrode material for spintronic applications. In particular, the composition La_0.67Sr_0.33MnO₃ was used in spintronic devices due to the nearly 100 % spin polarization at the Fermi level [2]. Here LSMO films with varying film thicknesses between 10 nm and 300 nm were deposited by magnetron sputtering at room temperature on silicon substrates covered with a native oxide. The films were annealed in ambient atmosphere at 775 ^∘C for 20 min, 1 h, 3 h, and 9 h. Afterwards the layers were investigated by spectroscopic ellipsometry, magneto-optical Kerr effect spectroscopy and magnetometry. The main goal of this work is to understand how the magnetic properties, the dielectric function, and the magneto-optical response of post deposition annealed LSMO are influenced by the layer thickness and annealing time. The results show that the magnitude of the off diagonal elements of the dielectric tensor decreases drastically when the layer thickness is smaller than 20 nm. Furthermore, the remanence and coercive field increase with annealing time for films thicker than 20 nm. [1] E. Dagotto et al. Physics Reports 344 (2001) [2] J.-H. Park et al. Nature Vol 392 (1998)