Lattice thermal conductivity and phonon-dislocation interaction in niobium and tantalum single crystals plastically deformed at intermediate temperatures

Abstract

The thermal conductivity of niobium and tantalum single crystals plastically deformed in steps at intermediate temperatures has been measured in the temperature range 0.3 to 20 K. From these measurements the thermal resistivity W _d induced by the plastic deformation was calculated in the temperature range 0.3 K < T < 5 K. After each deformation step a thermal resistivity W _d proportional to T ⁻² was found. The dislocation arrangement was studied by X-ray topography and transmission electron microscopy. The results are consistent with a model of phonon scattering by the static distortion field of dislocations.