  Extending the current understanding and use of magnonics beyond conventional
planar systems, we demonstrate surface localization of spin-wave ferromagnetic
resonance (FMR) modes by designing complex three-dimensional nanostructures.
Using micromagnetic simulations, we systematically investigate woodpile-like
scaffolds and gyroids - periodic chiral entities characterized by their triple
junctions. The study highlights the critical role of demagnetizing fields and
exchange energy in determining the FMR responses of 3D nanosystems, especially
the strongly asymmetric distribution of the spin-wave mode over the system
height. Importantly, the top-bottom dynamic switching of the surface mode
localization across the structures in response to changes in magnetic field
orientation provides a new method for controlling magnetization dynamics. The
results demonstrate the critical role of the geometric features in dictating
the dynamic magnetic behavior of three-dimensional nanostructures, paving the
way for both experimental exploration and practical advances in 3D magnonics.
