Enhancement of superconductivity in disordered films by parallel magnetic field

We show that the superconducting transition temperature Tc(H) of a very thin highly disordered film with strong spin-orbital scattering can be increased by a parallel magnetic field H. This effect is due to the polarization of magnetic impurity spins, which reduces the full exchange scattering rate of electrons; the largest effect is predicted for spin-1/2 impurities. Moreover, for some range of magnetic impurity concentrations, the phenomenon of superconductivity induced by magnetic field is predicted: the superconducting transition temperature Tc(H) is found to be nonzero in the range of magnetic fields 0 < H* ≤ H ≤ Hc.