Minigap in a superconductor–normal metal junction with paramagnetic impurities

We study the effect of spin-flip scattering on the density of states in a long diffusive S-N junction with transparent interface. We calculate the critical value of the spin-flip scattering rate at which the minigap closes and give the dependence of the minigap on the spin-flip rate. For the system we consider, the minigap and the critical spin-flip rate have the scale of the Thouless energy, and not of the superconducting gap.