We present a Brillouin light scattering investigation of the eigenmode spectrum of nanometric permalloy rings as a function of the applied magnetic field. In particular, different splitting effects induced by the applied magnetic field on the radial and azimuthal excitations have been observed and explained in terms of either mode localization or symmetry. The dynamical matrix approach has been used to calculate the whole set of eigenvectors and eigenvalues of the system, in both the vortex and saturated states.

• Received 20 July 2006

DOI:https://doi.org/10.1103/PhysRevLett.97.247203