Marchenko A. Static and dynamic properties of ferromagnetic antidot lattice: symmetry effects

Static and resonance properties of ferromagnetic films with lattice of antidots (pores in the film) of different symmetry have been studied. The description of the system is based on micromagnetic modeling and analytical solutions of the Landau-Lifshitz equation. An original method for calculation of the ferromagnetic antidot lattices characteristics is used. It is found that the antidot pattern induces an apparent configurational anisotropy manifesting itself via an anisotropic resonant response of the patterned film. Micromagnetic simulations showed an inhomogeneous magnetization distribution within a unit cell of the antidot lattice, which can be represented as a few uniformly magnetized regions ("domains"). The number of domains, their form, and their symmetry are determined by the antidot lattice symmetry. The influences of the lattice symmetry and system parameters on structure of FMR spectra have been analyzed. It was shown that, for low damping, the resonance spectra contain a few quasi-homogeneous modes which are due to the resonance of different regions of the antidot lattice cell. The angular field dependences of each mode are characterized either as a twofold symmetry or as the lattice's symmetry. In total, symmetry of the lattice is realized in static and dynamic magnetic characteristics. The shape of the spectrum and the resonance frequencies of the domains depend on an external magnetic field orientation in the film's plane, too. The FMR line-width, domain anisotropy, and antidot lattice anisotropy are also functions of the lattice parameters, film thickness, and antidots radius.