Accession Number : AD0642104

Title :   ULTRASONIC ATTENUATION OF PURE STRONG-COUPLING SUPERCONDUCTORS.

Descriptive Note : Technical rept.,

Corporate Author : RUTGERS - THE STATE UNIV NEW BRUNSWICK N J DEPT OF PHYSICS

Personal Author(s) : Woo,James W. F.

Report Date : NOV 1966

Pagination or Media Count : 29

Abstract : The low frequency longitudinal ultrasonic attenuation of strong-coupling superconductors is discussed. The starting point is a formula due to Kadanoff and Falko which expresses the attenuation in terms of various correlation functions. These functions were evaluated in the ladder approximation. The results are valid for all values of ql (l-electron mean free path, q-phonon wave number). In the ql >> 1 limit, the contribution of the density-density correlation function is dominant and Ambegaokar's result is obtained for the reduced attenuation (ratio of attenuation in superconducting to normal states). In the ql << 1 limit, all correlation functions are equally important. The reduced attenuation is a function of q and differs from the results of the BCS isotropic model. Numerical calculations for the reduced attenuation in lead was performed for various values of q which satisfies ql << 1. The results are in rough agreement with that of Deaton's experiment. (Author)

Descriptors :   (*SUPERCONDUCTORS, ULTRASONIC PROPERTIES), (*ULTRASONIC RADIATION, ATTENUATION), STRESSES, TENSOR ANALYSIS, INTEGRAL EQUATIONS, FUNCTIONS(MATHEMATICS), APPROXIMATION(MATHEMATICS), CRYSTAL LATTICES, PHONONS, WAVE FUNCTIONS

Subject Categories : Acoustics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE