Resonant scattering of thermal phonons by dislocations in superconducting aluminum

Measurements of the lattice thermal conductivity in superconducting Al demonstrate the existence of a resonant phonon-dislocation interaction near ${10}^{10}$ Hz. Three different models of dislocations, each exhibiting an eigenfrequency, may be made to agree with the data. It is suggested that the dynamical behavior of dislocations at thermal amplitudes, as observed in the present measurements, may differ from the dynamical properties appropriate to ultrasonic and other techniques which employ macroscopic strain amplitudes.