Velocity angular dispersion of surface and bulk acoustic modes in SrTiO3

The velocity angular dispersion of Rayleigh surface and bulk acoustic modes propagating parallel to the surfaces of (100), (110) and (111) SrTiO3 plates has been measured by surface Brillouin scattering. Transverse bulk acoustic modes propagating in certain directions are not detected in the scattering geometry employed. The nonobservation of these modes is consistent with results of a calculation of their scattering coefficient. A simultaneous fit to the experimental data on the bulk acoustic modes for the three crystal orientations yields elastic constants that are used to accurately predict the various velocity angular dispersion branches of the Rayleigh surface mode. (C) 2003 American Institute of Physics.