Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 26: Spin Dynamics / Spin Torque IV
MA 26.5: Vortrag
Donnerstag, 25. März 2010, 15:30–15:45, H10
Reversible folding of acoustic spin waves in an one-dimensional magnonic crystal — •Jesco Topp1, Mikhail Kostylev3, Detlef Heitmann1, and Dirk Grundler2 — 1Institut für Angewandte Physik, Universität Hamburg, 20355 Hamburg, Germany — 2Physik-Department E10, Technische Universität München, 85747 Garching, Germany — 3School of Physics, M013, University of Western Australia, 35 Stirling Hwy, 6009 Crawley, WA, Australia
Spin waves can be tailored by geometric confinement, through inhomogenuous internal fields or bandstructure engineering in magnonic crystals, i.e. periodic arrays of magnetic structures that support spin-wave propagation from structure to structure. We have investigated spin waves in a one-dimensional magnonic crystal fabricated out of from 300 nm wide and 20 nm thick nanowires and investigated the magnetic-field dispersion near the Brillouin-zone center by means of broadband microwave spectroscopy. The spin-wave spectrum of this crystal can be controlled by (reversibly) modifying the bandstructure of the crystal during the experiment. We find that two different kinds of spectra can be chosen, depending on the unit cell of the crystal. A simple cell (a single wire) or a complex one (two wires with antiparallel magnetization) can be selected using a careful magnetic-field history. Modes of the complex unit cell can be understood by a folding of the (simple cell's) wavevector dispersion into the new Brillouin zone. The lowest-order acoustic spin wave and its folded counterpart exhibit a peculiar magnetic-field dispersion. Funding via "SFB 668" and the "Nanosystems Initiative Munich" (NIM) is acknowledged.