ULTRASONIC ATTENUATION AT LOW TEMPERATURES IN POTASSIUM AND GOLD.
CALIFORNIA UNIV LOS ANGELES DEPT OF PHYSICS
Pagination or Media Count:
The present investigation is primarily an experimental study of the electron-lattice ultrasonic attenuation in potassium. The results indicate that the attenuation is higher than predicted by a factor of 1.6, with an experimental uncertainty of 10. A study was also made, in both potassium and gold, of a strain amplitude-dependent attenuation which was present at liquid helium temperature and the results for this effect are in general agreement with the theoretical expectations. The values of the constants of the Granato-Lucke theory are given. Additional features of the ultrasonic absorption between 20 degrees K and 77 degrees K are discussed in terms of some theories of dislocation motion. The ideal electrical resistivity in potassium below approximately 7 degrees K is found to have a T to the 5th power dependence at higher temperatures the dependence decreases and becomes about T to the 3rd power at 20 degrees K. The data agree within 5 with the Hasegawa theory between 4 degrees K and 20 degrees K.
- Solid State Physics