Superconducting properties of In-Ge mixture films

We report on measurements of the perpendicular H_c⊥ and parallel Hc? upper critical fields of superconducting In-Ge mixture films in a wide range of In concentrations. The resistivities of the samples varied from about 10 {μ}{Ω}?, corresponding to high In concentration, up to about 1300 {μ}{Ω} cm, corresponding to an In concentration close to the percolation threshold of the system. The critical temperatures of the samples in a zero external field have also been studied. For high metal concentrations the results have been analyzed and found to fit the predictions of the dirty limit for type-II superconductors. Near the threshold, however, where the normal-state resistivity goes to infinity, the critical fields saturate to a finite value. This result is in accordance with the prediction of percolation theory in the anomalous diffusion regime. As the threshold is approached the anisotropy ratio decreases to a constant value of 1.2 from its homogeneous type-II limit 1.69.