ACOUSTIC ATTENUATION IN HIGH-T-C SUPERCONDUCTORS

We analyze the acoustic-attenuation rate in high-T-c superconductors, and find that this method offers an additional way to examine the anis otropy of the superconducting order parameter in these materials. We a rgue that it should be possible to distinguish the electronic contribu tion to the acoustic attenuation, which has a strong temperature depen dence near T-c, from the lattice contribution, which does not show a s trong temperature dependence near T-c. We propose that this can be uti lized to measure the anisotropy of the order parameter by measuring th e attenuation rate near T-c in different directions.