The coherent transport of spin information is one of the great challenges in condensed matter physics and is of fundamental importance for the development of spintronic devices. Spin waves carry angular momentum and can be used to transport spin information over mesoscopic distances much larger than the spin diffusion length in metals. The energy dispersion of spin waves in thin films is highly anisotropic due to dipolar interactions. As a consequence spin waves typically only propagate along straight lines, which hinders the implementation of more complex two-dimensional device-structures. In order to overcome this problem, we use locally generated magnetic Oersted fields to alter the magnetization direction solely in designated regions of the spin wave conduits. This enabled us to tailor the dispersion relation in different parts of the structure for controlling the spin wave propagation. The feasibility of this concept is demonstrated by detecting the propagation of the spin wave with spatially resolved Brillouin light scattering spectroscopy. This work opens the door to more complex devices utilizing the unique properties of spin waves and thus is a significant stepping-stone towards designing functional spin wave structures.
Realization of a spin-wave multiplexer,
K. Vogt, F.Y. Fradin, J.E. Pearson, T. Sebastian, S. D. Bader, B. Hillebrands, H. Hoffmann, and H. Schultheiss,
Nature Comm. 5, 3727 (2014)