Magnetic normal modes of elliptical NiFe nanorings studied by micro-focused Brillouin light scattering

Micro-focused Brillouin light scattering (micro-BLS) technique is employed to study the magnetization dynamics of a single elliptical NiFe nanoring. Spin waves spectra, recorded at different positions within the ring, compare very well to the results of dynamical micromagnetic simulations, confirming the exact spatial symmetry and localization region of each of the detected modes. In addition, a comparison with the spectra acquired by conventional Brillouin light scattering on a large array of identical nanorings enables us to show the superiority of micro-BLS for the study of stationary and localised modes within nanomagnets.