Aperiodic magnonic crystals, namely magnetic fractals, lack long-range order and produce complex and localized spin-wave spectra. However, to achieve the spin-wave propagation in such magnetic fractals, it is important to enhance the exchange coupling at the interface by introducing two different ferromagnetic materials. In this work, we report the magnetization dynamics of the bicomponent Sierpiński square structure consisting of $\mathrm{Co}\mathrm{Fe}$ inclusions within a $\mathrm{Ni}\mathrm{Fe}$ matrix by solving the Landau-Lifshitz-Gilbert equation using micromagnetic simulations. The time domain magnetization data show the presence of multiple small and wide frequency gaps in the spin-wave spectra. In addition, the spatial profile of the spin-wave mode exhibits a self-similarity at various geometrical scaling for different iterations and a spin-wave channeling along the entire length of the structure, which could further be tuned by varying the azimuthal angle of the external magnetic field. The complex and inhomogeneous demagnetization field arising from aperiodic structuring significantly influences the spin-wave dynamics in these magnetic fractals. These findings demonstrate the potential application of the bicomponent Sierpiński square structure in reconfigurable magnonic device applications.

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• Magnons
• Spin dynamics
• Spin waves
• Ferromagnets
• Fractals
• Magnonic crystals
• Quasicrystals
• Micromagnetic modeling