Fluctuation-induced diamagnetism in bulk isotropic superconductors at highreduced temperatures

The short-wavelength effects on the fluctuation-induced diamagnetism (FD) i n bulk isotropic three-dimensional (3D) superconductors are taken into acco unt by introducing in the Gaussian-Ginzburg-Landau approach different cut-o ff conditions. These calculations, which extend to the 3D case our previous results on layered superconductors, are then used to briefly analyse the F D data measured for the low-temperature superconducting alloy Pb-8 at.% In. These analyses confirm the adequacy of a total-energy cut-off for explaini ng, for low-temperature 3D superconductors also, the,thermal fluctuation ef fects in the high-reduced-temperature region. These results thus provide fu rther support to the recent proposal that, due to the localization energy, the size of the effective fluctuations cannot be appreciably smaller than t he superconducting coherence length amplitude extrapolated to T = 0 K.