Tunable Angle-Dependent Magnetization Dynamics in Ni80Fe20 Nanocross Structures of Varying Size

We demonstrate a large angular dependence of magnetization dynamics in Ni80Fe20 nanocross arrays of varying sizes. By subtle variation of the azimuthal angle (φ) of an in-plane bias magnetic field, the spin configuration and the ensuing spin-wave dynamics, including mode softening, mode splitting, mode crossover, and mode merging, can be drastically varied to the extent that a frequency minimum corresponding to mode softening converts to a mode crossover, various mode splitting and mode crossover disappear, and additional mode splitting appears. Numerically simulated spin-wave spectra and phase profiles reveal the nature of various spin-wave modes and the origin of the above variation of the dynamics with a bias-field angle. All of these above observations are further modified with the variation of the dimensions of the nanocross. The numerically calculated magnetostatic field distributions further support the variation of dynamics with a bias-field angle. These results open an avenue for engineering nanocross-based magnetic devices such as magnetic storage, spin-wave logic, and on-chip data communication devices.