Influence of high magnetic fields on the superconducting transition of one-dimensional Nb and MoGe nanowires

The effects of a strong magnetic field on superconducting Nb and MoGe nanowires with diameter ~10 nm have been studied. We have found that the Langer-Ambegaokar-McCumber-Halperin (LAMH) theory of thermally activated phase slips is applicable in a wide range of magnetic fields and describes well the temperature dependence of the wire resistance, over 11 orders of magnitude. The field dependence of the critical temperature, Tc, extracted from the LAMH fits is in good quantitative agreement with the theory of pair-breaking perturbations that takes into account both spin and orbital contributions. The extracted spin-orbit scattering time agrees with an estimate τs.o. ~ τ (hc/Ze2)4, where τ is the elastic scattering time and Z is the atomic number.