Brillouin scattering from single crystal Cu/Ni superlattices

Rayleigh waves of single crystal Cu/Ni superlattices have been studied by Brillouin scattering. The Rayleigh wave propagating along the [ 1 1 ¯ 0 ] direction on the (1 1 1 ) surface shows an anomalous increase of the velocity around the modulation period of 40A. On the other hand, no modulation period dependence has been observed for the Rayleigh wave propagating along the [1 0 0] direction on the (0 0 1) surface.