Spin dynamics of multilayered nanoelements with different shapes studied by Brillouin light scattering technique

A Brillouin light scattering experimental investigation of the high-frequency dynamical properties of Ni81Fe19(10 nm)/Cu(10 nm)/Ni81Fe19(10 nm) patterned elements (stripes, rectangles, squares) with sub-micrometric lateral dimensions is reported. A number of discrete peaks, corresponding to the resonant frequencies of the trilayered nanostructures, have been observed in the measured spectra. Both the frequency and the spatial profile of these modes were calculated by either analytical or numerical methods, achieving a satisfactory comparison between theory and experiment. In particular, the numerical simulations enabled us to classify the modes into two main families, according to the in-phase or out-of-phase magnetization precession in the two magnetic layers, and to correlate the localization region of the dynamical modes with the inhomogeneity profile of the internal magnetic field.