Refine
Year of publication
- 1997 (2)
Language
- English (2) (remove)
Has Fulltext
- yes (2)
Faculty / Organisational entity
We report on the observation of quantized surface spin waves in periodic arrays of magnetic Ni81Fe19 wires by means of Brillouin light scattering spectroscopy. At small wavevectors (q_1 = 0 - 0.9*100000 cm^-1 ) several discrete, dispersionless modes with a frequency splitting of up to 0.9 GHz were observed for the wavevector oriented perpendicular to the wires. From the frequencies of the modes and the wavevector interval, where each mode is observed, the modes are identified as dipole-exchange surface spin wave modes of the film with quantized wavevector values determined by the boundary conditions at the lateral edges of the wires. With increasing wavevector the separation of the modes becomes smaller, and the frequencies of the discrete modes converge to the dispersion of the dipole-exchange surface mode of a continuous film.
The first observation of self-focusing of dipolar spin waves in garnet film media is reported. In particular, we show that the quasi-stationary diffraction of a finite-aperture spin wave beam in a focusing medium leads to the concentration of the wave power in one focal point rather than along a certain line (channel). The obtained results demonstrate the wide applicability of non-linear spin wave media to study non-linear wave phenomena using an advanced combined microwave-Brillouin light scattering technique for a two-dimensional mapping of the spin wave amplitudes.