Thermal conductivity and electrical resistivity of Nb-Ti (HT-50) as a function of temperature and magnetic field

Measurements have been made of the thermal conductivity and electrical resistivity of wires 10 μm and 112 μm in diameter from a composite superconducting cable and of a bulk sample of Nb-Ti of the HT-50 type. The temperature range of the measurements was 4 K - 25 K and the magnetic field ranged up to 7 T. It was found that technical superconductors of the same type (HT-50) but of various geometrical constructions had different values of thermal conductivity, residual resistivity and critical temperature. The thermal conductivity in the superconducting state was field-independent at fields up to 7 T, and decreased for T > Tsub(c) with increasing field. The residual resistivity was independent of fields up to 7 T. (author)