Magnonic Band Structure and Filtering Properties of Square Antidot Lattices in Different Configurations: A Micromagnetic Study

We present the results of advanced micromagnetic simulations, performed using the open-source GPU-accelerated code MuMax
³
, on spin waves excitation and propagation in two-dimensional magnonic crystals consisting of Permalloy (Ni
₈₀
Fe
₂₀
square antidot lattices. The magnonic band structure of samples having a fixed periodicity a = 200 nm and different sides of the square holes, ranging from 30 to 90 nm, has been analyzed in both the magnetostatic surface wave and backward volume wave configurations, encompassing the first three artificial Brillouin zones. A careful analysis of both the dispersive character and the spatial profile of the most prominent eigenmodes permits interpretation of the main features of the transmission spectra of the simulated samples, which can be considered tunable magnonic filters. General conclusions are drawn about the choice of the optimal geometry for the design of signal processing devices based on square antidot lattices.