Abstract
Thermoelectric measurements with thermocouples consisting of thin platinum foils and 0.254-mm-diam platinum wire have been carried out between 4.2 and 310°K. The thickness of the foils was 1.6× to 8× mm. The difference between the thermoelectric power of the foils and the wire was separated into the electronic component , caused by the electron scattering at the crystal surface, and the phonondrag component , resulting from the phonon scattering at the crystal surface. From the phonon-drag component the phonon mean free path in the bulk material was determined as a function of the temperature. Above 60°K (approximately the temperature of the phonon-drag peak) the relation mm was found, in agreement with the expectation that in this temperature range is mainly limited by phonon-phonon umklapp processes. The pre-exponential factor in is within a factor of two in agreement with the value calculated from Klemens's theory. From the electronic component , the derivative of the electron mean free path with respect to the electron energy was found to be . Measurements of the electrical-resistivity difference between the foils and the wire yielded for the electron mean free path in platinum the value cm at 296°K.
- Received 7 July 1965
DOI:https://doi.org/10.1103/PhysRev.140.A1834
©1965 American Physical Society