Controlling magnon propagation and frequency gap through the fan angle of a sinusoidal bias field

We investigate through micromagnetic simulations the spin-dynamics of a ferromagnetic film to which a sinusoidal magnetic field is applied with fixed magnitude and variable fan angle Θ F . At equilibrium, the magnetization relaxes in a likewise sinusoidal distribution with an amplitude depending on Θ F . We illustrate in detail how the dispersion curves and the frequency gap at zone boundary vary with Θ F , discussing the functional behavior and the correlation to the potential energy density. We also discuss the extent and limits to which the Kittel formula can be used in computing the resonance frequencies even for sinusoidal magnetizations, definitely far from being uniform. In conclusion, we demonstrate that it is possible to achieve full control on magnon propagation through Θ F as a sole degree of freedom. This allows to keep the field magnitude constant and small, reducing energy dissipation at a minimum, with positive implications for dissipationless magnon-devices. • Full control of magnon dynamics through the sole fan angle of a sinusoidal applied field. • The magnon frequency dispersion curves shift to lower frequencies with increasing fan angle. • The frequency gap shows a quadratic dependence on the fan angle. • The Kittel formula for the FMR can be still used for sinusoidal magnetizations with some limits. • Varying the fan angle at a fixed and small field magnitude can be useful in the perspective of minimizing the energy dissipation. • The magnetization fan angle can be varied through electric current intensity