. . . . . . . . . .    ANM 2010     3rd International Conference on Advanced Nano Materials     12-15 September 2010 - Agadir, Morocco Back    Abstract ANMM112 MAGNETIC NANOWIRES FORMING A RECONFIGURABLE ARTIFICIAL CRYSTAL J. Topp,1 D. Heitmann,1 M. Kostylev,2 and D. Grundler3 1 Institut fuer Angewandte Physik, Universitaet Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany; 2 School of Physics, M013, University of Western Australia, 35 Stirling Hwy, 6009 Crawley, WA, Australia; 3 Physik Department E10, Technische Universitaet Muenchen, James-Franck-Str., D-85747 Garching, Germany . Spin dynamics in ferromagnetic nanodevices is of great current interest. It is relevant for, both, current applications in spintronics such as spin valves as well as future developments in magnonics where spin waves (magnons) instead of electrons or photons are used to transmit and process information. Since spin waves possess ultrashort wavelengths if compared to electromagnetic waves at the same frequency magnonics offer microwave devices operating on the nanoscale. Here, a magnonic crystal, i.e., the magnetic counterpart of the photonic crystal, is of particular interest. By periodic nanopatterning of magnetic material one might generate a tailored band structure for spin waves consisting of allowed bands and forbidden frequency gaps. We have fabricated closely packed arrays of ferromagnetic nanowires out of Ni80Fe20. These nanowires are 20 nm thick, 300 nm wide and have an edge-to-edge separation of 100 nm. Using broadband spin wave spectroscopy we find that such arrays form a one-dimensional magnonic crystal. Strikingly, we observe two different kinds of magnon spectra. The spectra depend on the magnetic history and ordering of neighboring wires, i.e., parallel and antiparallel alignment. At zero in-plane magnetic field the modes of the antiparallel case can be understood by the zone folding of the spin-wave dispersions of the parallel case. This is no longer true for a non-zero in-plane field which opens a forbidden frequency gap at the Brillouin zone boundary. We substantiate the reprogrammable magnonic crystal behavior by numerical calculations. The recon¬figuration offers new perspectives for multifunctional magnonic devices. The work has been supported by SFB 668, FP7/2007-2013 (Grant Agreement no. 228673, MAGNONICS) and the Excellence Cluster “Nanosystems Initiative Munich (NIM)”. . © nanoAC . . . . . . . . . .

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