Thermal conductivity of NbTi alloy in the low‐temperature range

The temperature dependence of the thermal conductivity of a NbTi (50/50) superconductor is measured in the temperature range from 1.3 to 300 K in two different laboratories. From the analysis of the experimental results it follows that the electron processes provide the main contribution to the thermal transport in the range above 0.3Tc while phonon contribution is decisive, due to the defect structure, only below this temperature. The values of energy gap 2Δ = (2.15 to 2.3) kTc are found by three independent methods. Further, the temperature dependence of the thermal diffusivity is presented in the temperature range above 4 K.