Sound propagation in heavy fermion compounds

Sound propagation experiments are used to investigate the superconducting (sc) phases of Heavy Fermion (HF) compounds. Velocity measurements lead to accurate B-T phase diagrams and results for the temperature dependent attenuation of all modes in UPt3 are presented. In addition to the strain-order parameter interaction for longitudinal modes there is a Lorentz force coupling of transverse modes to the normal electrons. It leads to a B-dependence of velocity and attenuation from which information about both London and skin penetration depth in URu2Si2 and UBe13 may be obtained. In UBe13 magnetoacoustic quantum oscillations are observed which prove the coexistence of light and heavy electrons in this compound. (orig.)