Electronic Thermal Conductivity of Superconducting Thin Films of Indium-Manganese Alloys

The transition temperature Tc and the thermal conductivity of thin films of superconducting indium and indium-manganese alloys have been measured at temperatures from 1.2 to 4.2 K. The films contained 0.0-0.0567 at.% manganese. They were quench condensed on thin substrates at 4 K, and were kept below 5 K throughout the measurements. The dependence of Tc on manganese concentration is in excellent accord with the theory of Abrikosov and Gor'kov. However, the thermal-conductivity data are in systematic disagreement with the theory of Ambegaokar and Griffin and of Bennemann. This observation is related to discrepancies with theory which have been seen in the results of other experiments on the effect of transition-element magnetic impurities. Some approximations in the theory are listed which may account for the difficulty.