Evolution of the ferromagnetic resonance spectrum of a hexagonal antidot lattice with film thickness: Experiment and numerical simulations

Experimental and theoretical studies of the evolution of the ferromagnetic resonance spectrum with film thickness for hexagonal lattice of antidots have been reported. We found three different quasi-uniform modes in the resonance spectrum. Calculations of the local dynamic susceptibility tensor show that these modes are related to the resonances from quasiuniformly magnetized regions of the hexagonal antidot array unit cell. The increase of the film thickness results in the broadening of the resonance lines as well as the appearance of additional resonance lines. Good qualitative correlation of the theory and experiment was obtained. Additional relaxation mechanisms due to magnetic inhomogeneities are also discussed.