Temperature dependence of the excess resistivity and thermopower in dilute alloys of tungsten. I. Experimental results

Abstract

Excess resistivities and relative thermopowers are measured on dilute alloys of tungsten with Fe, Co, Ni, Al and Pt and on W-4 at.% Mo and W-2 at.% Re alloys in the temperature range of about 4-300 K. The majority of these alloys reveal large deviations from Matthiessen's rule in the low temperature range (within about 20-100 K). In the less dilute WMo and WRe alloys large linear deviations from Matthiessen's rule are observed at higher temperatures, which may be attributed to a change in the phonon spectrum due to impurities. In dilute alloys the relative thermopower curves are almost linear at the lowest temperatures, almost independent of concentration and go down to zero at about T=5 K, except WFe. After the linear stage the thermopower curves are separated, and a large peak occurs in the vicinity of 30 K. At higher temperatures the relative thermopowers decrease, while at 300 K they become almost proportional to the concentration, which may be expected for dilute alloys from the Nordheim-Gorter rule.