We propose an alternative micromagnetic approach to determine the spin wavedispersion relations in magnonic structures. Characteristic of the method isthat a limited area of the system is continuously excited with a spatiallyuniform oscillating field, tuned at a given frequency. After a transitory time,the regime magnetization dynamics is collected and a spatial Fourier analysison it determines the frequency vs wave vector relation. Combining severalsimulations in any predetermined range of frequencies, at any resolution, weinvestigate the dispersion relations for different kinds of magnonic crystals:a dot array, an antidot array, and a bicomponent film. Especially compared totraditional pulse-excitation methods this technique has many advantages. First,the excitation power is concentrated at a single frequency, allowing thecorresponding spin waves to propagate with very low attenuation, resulting in ahigher k-space resolution. Second, the model allows to include very large wavevector components, necessary to describe the high-frequency response ofnon-quantized spin waves in quasi-continuous systems. Finally, we address somepossible experimental opportunities with respect to excitation/detectiontechniques over large distances and the observation of the odd/even symmetry ofspin waves using Brillouin light scattering.
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