Microscopic study of magnetostatic spin waves

A relatively new method is developed to numerically calculate the spin-wave-related properties of a magnetic body of arbitrary shape. Starting with a discrete dipole approximation and the linearized Landau-Lifshitz equation, the resonant frequencies and the associated amplitudes of the individual moments are obtained for all modes; from this information we are able to calculate the energy absorbed by the various modes excited by a position- and time-dependent external magnetic field. The method has been demonstrated for a number of cases including thin disks and rings and for equilibrium configurations ranging from the saturated high-field limit to the vortex states at low fields.