Temperature and Mean-Free-Path Dependence of the Upper Critical Field in Indium-Lead Alloys

Measurements of the specific heat of In: Pb alloys of varying lead concentration were used to deduce the temperature and mean-free-path dependence of Maki's parameter ${\kappa }_1$. The most impure sample showed the strongest temperature dependence of ${\kappa }_1$ in complete disagreement with existing theories.