Landau-Khalatnikov Damping of Ultrasound in Heavy-Fermion Superconductors

Abstract

The Landau-Khalatnikov mechanism associated with the relaxation of the order-parameter amplitude gives a peak in the longitudinal ultrasonic attenuation $\alpha$ near $T_c$, which quantitatively accounts for the observed peak in U${\mathrm{Be}}_{13}$ and U${\mathrm{Pt}}_3$. At lower temperatures this mechanism gives a power-law attenuation.