Ultrasonic Attenuation of Transverse Waves in V, Nb, and Ta forql<1

Abstract

The temperature dependence of the ultrasonic attenuation coefficient of transverse waves with a wave vector parallel to (110) was measured in superconducting V, Nb, and Ta. The product of the wave vector times the mean free path q1 was smaller than one during these measurements. The sharp drop in the attenuation Foefficient below the trsnsition temperature, which is found when ql > 1, was not present. The zero-temperature energy gap was found to be 3.6 plus or minus 0.2 kT/sub c/ for V, 3.5 plus or minus 0.3 kT/sub c/ for Nb, and 3.5 plus or minus 0.2 kT/su b c/ for Ta. (auth)