Spin-wave modes and band structure of rectangular CoFeB antidot lattices

We present an investigation of rectangular antidot lattices in a CoFeB film. Magnonic band structures are numerically calculated, and band gaps are predicted which shift in frequency by 0.9 GHz when rotating the external field from the long to the short axis of the unit cell. We demonstrate by time-resolved experiments that magnonic dipolar surface modes are split in frequency by 0.6 GHz which agrees well with the theoretical prediction. These findings provide the basis for directional spin-wave filtering with magnonic devices.