Bondarenko P. Spin dynamics of ordered arrays of the dipole coupled submicron magnetic particles.

The dissertation is devoted to the theoretical study of collective magnonic modes in the magnetic dot arrays, where the small magnetic particles are organized in the rectangular lattice. The magnetic oscillations spectrum was calculated for chessboard antiferromagnetic ordered array of magnetic dots with a perpendicular anisotropy in the presence of external magnetic field directed along the easy axis. The general characteristics of the dispersion relation are described. The density of states in the antiferromagnetic ordered and saturated arrays was calculated. The non-standard singularities of the density of state, additionally to usual two-dimensional Van Hove singularities, were found. The special boundary modes (collective modes localized on a boundary of 2D magnetic dot arrays) in both ground states, saturated and antiferromagnetic, were predicted. Stability of the different ground states was analyzed on the basis of the spectra. This allowed constructing the phase diagram for the magnetic dot array on the plane with the coordinates the anisotropy constant-magnetic field. The eigenmodes of collective oscillations in the arrays of elements with planar magnetization are calculated at the strong coupling approximation. The results are compared with those obtained using direct numerical simulations, yielding a good agreement.