Thermal and Electrical Transport in a Tungsten Crystal for Strong Magnetic Fields and Low Temperatures

Direct-current electrical and thermal transport coefficients were experimentally determined in a very pure tungsten crystal at six temperatures in the range 1.4-4.1 K and at magnetic fields up to 22 kOe. The field was applied along a [100] axis and each of the coefficients measured along an equivalent $〈100〉$ direction. Kinetic coefficients computed from the data were interpreted in terms of a Sondheimer-Wilson-type multiband relaxation-time model. The results were generally consistent with the extensive literature on the fermiology of tungsten. Galvanomagnetic data were approximately independent of temperature, a result implying elastic scattering and a common relaxation time for all transport effects, but the field dependence and magnitude of the thermal and Righi-Leduc resistivities were both distinctly less than those predicted by the Wiedemann-Franz law when a reasonable value of the lattice conductivity was assumed. A density of states computed from the Nernst-Ettingshausen coefficient was consistent with values reported from specific-heat measurements, but displayed an anomalous temperature dependence similar to that of the Righi-Leduc coefficient.