LAUSR

The current-voltage characteristics and dynamic conductance spectra of the SnS junction in Ba(Fe, Ni)2As2 superconducting pnictide of almost optimal composition have been obtained. A slight slope of the electronic density of states near the Fermi level has been detected. Using multiple Andreev reflection spectroscopy, we have directly determined the values and the temperature dependences of the two superconducting order parameters and estimated their anisotropy. We have shown that the obtained temperature dependences of Andreev excess current and Andreev zero-bias conductance could be fitted with a two-band model, and estimated the partial conductances of the two effective bands where the large and the small gaps are developed.