Dresden 2011 – wissenschaftliches Programm
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KR: Fachgruppe Kristallographie
KR 5: Poster Multiferroics (Joint Session of MA, DF, DS, KR, TT)
KR 5.18: Poster
Dienstag, 15. März 2011, 10:45–13:00, P2
Localized and delocalized modes in magnonic materials of hexagonal structure — •Fabian Garbs1, Benjamin Lenk1, Henning Ulrichs2, and Markus Münzenberg1 — 1I. Physikalisches Institut, Georg-August-Universität Göttingen — 2Institut für Angewandte Physik, Universität Münster
With the time resolved measurement of the magneto-optical Kerr effect (TRMOKE) the spin amplitude is detected until 1 ns after excitation. Dependence of the external magnetic field can be measured in the range of 0 ≤ µ0Hext ≤ 150 mT within an angle of up to 30∘ out of plane. The 50 to 150 nm thin samples were nanostructured with a focused ion beam (FIB) to lattices of hexagonal or honeycomb symmetry in the micrometer range.
The existence of antidots lead to new modes in micron-sized hexagonal structured thin films of Ni or CoFeB. Due to inhomogeneities in the internal field, localized spin-wave modes in nickel and propagating surface modes in the low damping CoFeB film occur. These modes are investigated for different structural parameters and varying alignments in the external field. In both cases the structural lattice is reflected in the measurements. One finds strong changes for directions of high symmetry. To clarify the influence of the symmetry, simulations have been done to show the internal field distribution.