DAMPING OF DISLOCATIONS IN NIOBIUM BY PHONON VISCOSITY.
Abstract
Attenuation measurements have been made of the body centered crystal niobium for three waves along the <110> direction. The room temperature measurements are consistent with dislocations lying in the (110) planes with glide directions along the <100> axes. The fast shear has the largest attenuation and it has been measured over a temperature range from 30K to 300K with frequencies from 10 MHz to 150 MHz. The attenuation can be divided into a square-law attenuation and a dislocation component. The dislocation component can be used to evaluate a drag coefficient which is nearly constant down to 78K. It rises at low temperatures indicating an electron drag effect. The constant region is consistent with a phonon viscosity damping with a crystal having a peak in the thermal conductivity. The electron drag confirms a theoretical calculation giving a drag inversely proportional to the electrical resistivity. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1970
- Accession Number
- AD0707786
Entities
People
- Douglas E. Macdonald
- Warren P. Mason
Organizations
- George Washington University