High-frequency susceptibility of soft ferromagnetic nanodots

The dynamic susceptibility spectra of a soft ferromagnetic nanodot supporting a vortex-type magnetic configuration is studied in the frequency range 0.1-20 GHz by means of dynamic micromagnetic simulations. The frequency evolution of the detected magnetic excitations as a function of both dot radius (40 less than or equal to R less than or equal to 160 nm) and dot thickness (5 less than or equal to L-z less than or equal to 80 nm) is reported. (C) 2003 Elsevier B.V. All rights reserved.