Electron diffusivities in MgB2 from point contact spectroscopy
  We demonstrate that the variation of the Andreev reflection with applied magnetic field provides a direct means of comparing the properties of MgB2 with the theory for a dirty two-band superconductor, and we find good agreement between the two. The ratio of electron diffusivities in the s and p bands can be inferred from this experiment. We find that the field dependence of the density of states at the Fermi level in the p band is independent of the field direction, and that the anisotropic upper critical field is determined by the anisotropic diffusivity in the s band. 
Y.Bugoslavsky, Y.Miyoshi, G.K.Perkins, A.D.Caplin, L.F.Cohen, A. V.   Pogrebnyakov, X. X. Xi