Surface Brillouin scattering of opaque solids and thin supported films

Surface Brillouin scattering (SBS) has been used successfully for the study of acoustic excitations in opaque solids and thin supported films, at both ambient and high temperatures. A number of different systems have been inv estigated recently by SBS including crystalline silicon, amorphous silicon layers produced by ion bombardment and their high temperature recrystallisa tion, vanadium carbides, and a nickel-based superalloy. The most recent dev elopment includes the measurement of a supported gold film at high pressure . The extraction of the elastic constants is successfully accomplished by a combination of the angular dependence of surface wave velocities and the l ongitudinal wave threshold within the Lamb shoulder. The application of sur face Green's function methods successfully reproduces the experimental SBS spectra. The discrepancies often observed between surface wave velocities a nd by ultrasonics measurements have been investigated and a detailed correc tion procedure for the SBS measurements has been developed. (C) 2000 Elsevi er Science B.V. All rights reserved.