  Spin waves offer intriguing novel perspectives for computing and signal
processing, since their damping can be lower than the Ohmic losses in
conventional CMOS circuits. For controlling the spatial extent and propagation
of spin waves on the actual chip, magnetic domain walls show considerable
potential as magnonic waveguides. However, low-loss guidance of spin waves with
nanoscale wavelengths, in particular around angled tracks, remains to be shown.
Here we experimentally demonstrate that such advanced control of propagating
spin waves can be obtained using natural features of magnetic order in an
interlayer exchange-coupled, anisotropic ferromagnetic bilayer. Using Scanning
Transmission X-Ray Microscopy, we image generation of spin waves and their
propagation across distances exceeding multiple times the wavelength, in
extended planar geometries as well as along one-dimensional domain walls, which
can be straight and curved. The observed range of wavelengths is between 1
{\mu}m and 150 nm, at corresponding excitation frequencies from 250 MHz to 3
GHz. Our results show routes towards practical implementation of magnonic
waveguides employing domain walls in future spin wave logic and computational
circuits.
