Elastic and magnetic properties of Co/Cu multilayers studied by Brillouin spectroscopy

The Brillouin light scattering technique has been used to investigate the elastic and magnetic properties of periodic Co/Cu multilayers deposited by rf sputtering on sapphire substrates. Using measurements of the phase velocity of the Rayleigh surface acoustic wave in p-p Brillouin spectra, we have evaluated the effective elastic constant c44. The values obtained for multilayer periods larger than 2 nm are in good agreement with those calculated from the elastic constants of the bulk materials. For lower periods (0.6 and 1.2 nm) the measured elastic constants exhibit marked decreases caused by interface disorder. Concerning the magnetic properties, in the case of high-period specimens, the detection of both surface and bulk spin waves in the p-s spectra has allowed us to determine the magnetic parameters of the multilayers