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MA: Fachverband Magnetismus
MA 3: Micro- and nanostructured Materials
MA 3.6: Talk
Monday, March 7, 2016, 11:00–11:15, H32
Enhanced Magneto-Optical Edge Excitation in Nanoscale Magnetic Disks — •Andreas Berger1, Rodrigo Alcaraz de la Osa2, Anna Suszka1, Matteo Pancaldi1, Jose Maria Saiz2, Fernando Moreno2, Hans Peter Oepen3, and Paolo Vavassori1,4 — 1CIC nanoGUNE — 2Universidad de Cantabria — 3Universität Hamburg — 4Ikerbasque
We report an unexpected enhancement of the magneto-optical effect for permalloy disks with a diameter D of less than 400 nm [1]. The effect becomes increasingly pronounced for smaller D, reaching more than a 100% enhancement for D = 100 nm samples. By means of simulations we are able to reproduce the experimental behavior, including its dependence on D, disk thickness t, wavelengths λ and diffraction order m. The simulations furthermore identify the origin of this effect as a ring-shaped region at the disk edges, where the magneto-optically induced electric polarization is enhanced [1]. This leads to an enhancement of the magneto-optical effect, independent from any optical resonance. The edge-induced enhancement effect is substantial, even if the absolute size of the magneto-optical effect in our samples remains modest. However, far larger absolute values should be achievable by utilizing materials with substantially larger magneto-optical coupling strengths Q and even smaller nano-scale dimensions or sub-structures.
[1] A. Berger et al., Phys. Rev. Lett. 115, 187403 (2015)