Experimental evidence of field-induced localization of spin excitations in NiFe elliptical rings by micro-focused Brillouin light scattering

Micro-focused Brillouin light scattering has been exploited as a scanning probe technique to investigate the spatial localization and symmetry of magnetic excitations in elliptical nanorings. The interpretation of the experimental data has been achieved using the dynamical matrix method. Special attention is paid to the investigation of the soft-mode involved in the vortex-to-onion transition, to the localization of modes as a function of the external field, and to the to identification of the vortex chirality of a single ring.