Localized phonon modes in Fe-Pd multilayer structures

Abstract

The Rayleigh mode and up to six higher-order localized acoustic (Sezawa) surface modes have been observed in Fe-Pd multilayer structures using Brillouin scattering. The effective elastic constants of the multilayer structures have been determined from a fit of the measured mode dispersions. With decreasing multilayer modulation wavelength from 87 to 33 \AA{}, the elastic constant ${c}_{11}$ shows an interface-induced softening of up to 20%.