Ultrasonic attenuation studies in super-conducting lead

Abstract

Measurements of the attenuation of 10, 30, 50 and 70 MHz longitudinal sound waves, propagated in the [100], [110] and [111] directions, have been conducted on the normal and superconducting states of high purity unstrained lead. Analysis of the data has been presented in such a manner as to allow for the possibility of multiple superconducting energy gaps. Our data indicate the existence of a secondary gap. The data have also been compared to theoretical calculations for both weak and strong coupling models. Measurements of the ultrasonic attenuation have also been conducted on a sample of strained lead for the [100] direction. Preliminary statements have been made with respect to strain effects and a simple descriptive model has been proposed.