Collective magnon modes for magnetic dot arrays

Both static and dynamic properties of the magnetic dot array with the uniform in-plane magnetization with the most symmetric configuration (round dots placed in a square lattice) have been investigated. Due to the long distance dipole coupling physical properties, such system has a strong four-fold anisotropy with respect both to orientation of the total array magnetization regarding the lattice symmetry axis and to the wave vector direction of a collective oscillations wave. The ferromagnetic state is stable only in the presence of the magnetic field; however, it can also be stable against small perturbations for some orientations of the total magnetization.