  Magnonics is gaining momentum as an emerging technology for information
processing. The wave character and Joule heating-free propagation of spin-waves
hold promises for highly efficient analog computing platforms, based on
integrated magnonic circuits. Miniaturization is a key issue but, so far, only
few examples of manipulation of spin-waves in nanostructures have been
demonstrated, due to the difficulty of tailoring the nanoscopic magnetic
properties with conventional fabrication techniques. In this Letter, we
demonstrate an unprecedented degree of control in the manipulation of
spin-waves at the nanoscale by using patterned reconfigurable spin-textures. By
space and time-resolved scanning transmission X-ray microscopy imaging, we
provide direct evidence for the channeling and steering of propagating
spin-waves in arbitrarily shaped nanomagnonic waveguides based on patterned
domain walls, with no need for external magnetic fields or currents.
Furthermore, we demonstrate a prototypic nanomagnonic circuit based on two
converging waveguides, allowing for the tunable spatial superposition and
interaction of confined spin-waves modes.
