Anisotropic 3D fluctuations conductivity in Bi2Sr2CaCu2O8+delta films

In zero applied magnetic field the fluctuation conductivity is measured and analyzed for a high-quality thin film (100 nm) of Bi2Sr2CaCu2O8+delta grow n, on a MgO substrate. The two-band model formulas derived by Konsin et al. for the temperature dependence of the anisotropic three-dimensional (3D) p araconductivity in the vicinity of a superconducting phase transition are u sed. One of the two correlation lengths is critical and along with the othe r parameters of the model it determines the fluctuation conductivity Delta sigma(T). The global result of two-band model mimics closely d-wave-type pa iring. The theory is compared with the experiment, and we obtained reasonab le values and the slope of Delta sigma(T), the superconducting critical tem perature T, and the coherence length xi(0).