New Absorption Phenomenon for Transverse Ultrasonic Phonons in Superconductors NearTc

The absorption of transverse ultrasonic waves in superconductors shows peaks rising considerably above the normal-state attenuation level when the temperature is near that of the superconductor-normal phase transition, $H\ne 0$, and the phonon polarization $\overrightarrow{\epsilon }$ satisfies specific boundary conditions. The observations are found to be consistent with a model attributing the enhanced absorption to a loss mechanism associated with relaxation of the Ginzburg-Landau order parameter.