The paraconductivity of granular Al-films at high reduced temperatures and magnetic fields

Abstract

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.

arXiv comment9 pages, 8 figures

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Cited by in corpus (3)

• Comment on 'Temperature range of superconducting fluctuations above $T_c$ in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ single crystals'
• On the dilemma between percolation processes and fluctuating pairs as the origin of the enhanced conductivity above the superconducting transition in cuprates
• Enhancement of superconductivity on thin film of Sn under high pressure