  The electrical conductivity induced near the superconducting transition by
thermal fluctuations was measured in different granular aluminum films. The
seemingly anomalous behavior at high reduced temperatures and magnetic fields
is explained by taking into account a total-energy cutoff in the
superconducting fluctuation spectrum in both the direct (Aslamazov-Larkin) and
the indirect (anomalous Maki-Thompson) contributions to the fluctuation
effects. The analysis allowed a reliable determination of the coherence length
amplitudes, which resulted to be much larger (20-48 nm) than the grains size
(5-10 nm). This suggests that the grains are strongly Josephson-coupled, while
the Tc value is still as high as twice the bulk value. These results could
contribute to identify the mechanisms enhancing Tc in these materials.
