Josephson effects in ultrashort mean-free-path superconductors

We show that it is possible to observe Josephson effects at temperatures up to 17 K in a superconductor with intrinsic mean free path <20 Å, contrary to what is generally thought possible. The temperature dependence of the critical current in Nb3Sn microbridges near Tc is consistent with predictions of the one-dimensional Ginzburg-Landau (ODGL) theory, while microwave-induced steps in the current-voltage characteristics are in excellent agreement with the resistively shunted junction (RSJ) model.