The absolute thermopowers and electrical resistivities of Ag-Pd and Cu-Ni have been measured as a function of temperature between 4.2 and 300°K for concentrations up to 20 at.%. The two systems behave differently in many respects. Matthiessen's rule is obeyed well for Ag-Pd but very poorly for Cu-Ni alloys. The phonon-drag peak is completely suppressed by the addition of less than 1 at.% Ni to Cu but persists to greater than 6 at.% Pd in Ag. Nordheim-Gorter plots are curved for both alloys, but related plots for fixed concentrations are linear, indicating that any given concentration the thermopower can be considered as arising from two nearly independent scattering mechanisms, both of which have characteristic thermopowers proportional to temperature. The results in general are consistent with a rather rapid initial change in the Fermi surface up to about 0.5 at.% followed by a more gradual modification. No marked anomalies which might coincide with the departure of the Fermi surface from the zone boundary have been observed.
ASJC Scopus subject areas
- Physics and Astronomy(all)