Thermal magnetoresistance of copper matrix in compound superconductors, a new measuring method

A technique is described which allows the surement of thermal conductivity of technical superconductors with little experimental effort to an accuracy of about 10 %. Results of thermal magnetoresistance of copper show that electrical and thermal conductivity follow the same field dependence. A simple analytical expression for the thermal conductivity of copper as function of residual resistivity ratio, magnetic field and temperature is given. In another experiment the thermal conductivity of an "in situ" Nb/Cu composite wire, a basic material for Nb3Sn conductors, was measured.