Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 5: Micro- and Nanostructured Magnetic Materials I
MA 5.4: Vortrag
Montag, 22. März 2010, 11:45–12:00, H23
Effects of hexagonal hole structures on magnetization dynamics in thin nickel films — •Fabian Garbs, Benjamin Lenk, Andreas Mann, Henning Ulrichs, Darius G. Vahdat-Pajouh, and Markus Münzenberg — I. Physikalisches Institut, Georg-August Universität Göttingen
The spin-wave modes in hexagonal magnonic structures in thin nickel films are investigated by ultra short laser pulses (60 fs). In an all optical pump-probe setup the pulses are used both to excite the sample and to observe the magnetic relaxation on the picosecond timescale up to 1 ns. By using the time resolved magneto-optical Kerr effect (TRMOKE) the magnetic oscillations are observed in external fields up to µ0Hext = ± 150 mT, under an angle of up to 30∘ out of plane.
The magnetic films are structured with periodic micron-sized holes to produce a magnetic metamaterial using a focused ion beam (FIB). Hole structures with different parameters (hole radius and periodic distance) were investigated. The hexagonal structure was chosen because of high symmetry and in comparison to results of rectangular structure experiments. Measurements under different in-plane angles reflect the structural symmetry in terms of the obtained field-dependent dispersion.
Furthermore a missing row in hole structures was investigated in order to find analogies to photonic waveguide behavior, which could be used prospectively for magnonic circuits.