Magnetic structure and resonance properties of a hexagonal lattice of antidots

Abstract

Static and resonance properties of ferromagnetic films with a hexagonal lattice of antidots (pores in the film) were studied. The description of the system is based on micromagnetic modeling and analytical solutions of the Landau–Lifshitz equation. The dependences of ferromagnetic resonance spectra on the in-plane direction of applied magnetic field and on the lattice parameters were investigated. The nature of the dependences of a dynamic system response on the frequency at fixed magnetic fields and on the field at fixed frequency when the field changes were explored. They cause the static magnetic order to change. It was found that the specific peculiarities of the system dynamics remain unchanged for both of these experimental conditions. Namely, for low damping the resonance spectra contain three quasi-homogeneous modes which are due to the resonance of different regions (domains) of the antidot lattice cell. It is shown that the angular field dependences of each mode are characterized by a twofold symmetry, and the related easy axes are mutually rotated by 60 °. As a result, a hexagonal symmetry of the system’s static and dynamic magnetic characteristics is realized. The existence in the resonance spectrum of several quasi-homogeneous modes related to different regions of the unit cell could be fundamental for the function of the working elements of magnonics devices.