In this paper we calculate the attenuation of high-frequency sound in clean type-II superconductors near the upper critical field $H_{c2\mathrm{}}$. The approach used is a generalization of that used by Brandt, Pesch, and Tewordt to calculate the density of states of a pure type-II superconductor. It is shown that the attenuation is strongly dependent on mean free path even if $l\gg {\xi }_0$. In the low-temperature limit we obtain a simple functional relationship between attenuation, mean free path, and magnetic field.

• Received 2 November 1970

DOI:https://doi.org/10.1103/PhysRevB.3.2997