Reprogrammable magnonic crystal - the new art to tailor band structures

An array of densely packed magnetic nanowires is found to form a new class of artificial crystal. It provides a stop-band functionality that goes beyond the ones known from electromagnetic waves in photonic crystals. We have shown that neighboring wires with parallel and anti-parallel magnetization form superstructures which exhibit different artificial band structures for spin waves. This has allows us to "reprogram" the stop bands in one and the same device. At the same time the size of the stop band is precisely tuned via an external means. This offers new perspectives in magnonics and solid state research. Here you can find an illustration on how a reprogrammable magnonic crystal works. The illustration is published in: J. Topp et al., Pure Appl. Chem. 83, 1989 (2011). [link to abstract]

Left: Working principle of a reprogrammable magnonic crystal. Ferromagnetic nanowires are shown in orange color. Green and red arrows indicate the orientation of a nanowire's magnetization. In purple color the local spin precession amplitudes are shown at a fixed time (in-plane components in x direction). The broken red line indicates the plane wave character. We show one and the same spin wave for three different magnetic scenarios. The spin wave is stopped when a forbidden frequency gap is opened by an in-plane magnetic field. This happens for the anti-parallel configuration of the magnonic crystal.
  [full article (pdf): click here. Copyright by American Physical Society]  

"Making a Reconfigurable Artificial Crystal by Ordering Bistable Magnetic Nanowires" 
  [full article (pdf): click here. Copyright by American Physical Society]
(Physical Review Letters 104, 207205 (2010))

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