Magnetic Transitions of Superconducting Thin Films and Foils. III. Pb, Sn, and In

Abstract

New measurements are reported for the superconducting-to-normal transition of Pb films to reduced temperatures ($\frac{T}{T_c}$) as high as 0.995. A comparison is made of the Ginzburg-Landau parameter, $\kappa$, for Pb, Sn, and In, derived from thin-film measurements (${\kappa }_F$) and values of $\kappa$ derived from supercooling and superheating studies (${\kappa }_{\mathrm{sc}}$) by Smith, Baratoff, and Cardona. The comparison reveals large discrepancies between ${\kappa }_F$ and ${\kappa }_{\mathrm{sc}}$, which is supported by similar measurements on Al by Maloney and de la Cruz. The discrepancy can be associated with a unique sensitivity of the thin-film transitions to nonlocality, but there is at present no rigorous theory.