Thermal conductivity of high-purity vanadium

The thermal conductivity, electrical resistivity, and Seebeck coefficient of four high-purity vanadium samples have been measured as functions of temperature over the temperature range 6 to 300 K. The highest-purity sample (resistance ratio 1524) had a thermal conductivity of 35 W/mK at room temperature and a maximum of 930 W/mk at 9 K. The electrical resistivity of our hydrogen-free vanadium showed no anomalous behavior above 130 K, in confirmation of Westlake's results. The Seebeck coefficient, which was positive from 10 to 240 K and negative above 240 K, had a maximum near 70 K which is characteristic of the phonon-drag effect. Our Seebeck-coefficient measurements are in general agreement with those of Mackintosh and Sill below 140 K, but differ significantly above 140 K. No hysteresis or discontinuity was observed in the Seebeck coefficient of these high-purity samples. The intrinsic electrical resistivity at low temperatures was due primarily to sd interband electron--phonon scattering. Vanadium, like niobium, is a superconductor; and we find that the transport properties of vanadium at low temperatures, like those of niobium, do not exhibit the electron--electron scattering characteristic of the nonsuperconducting transition elements