Effect of proton irradiation on superconductivity in optimally dopedBaFe2(As1−xPx)2single crystals (original) (raw)

Irradiation with 4-MeV protons was used to systematically introduce defects in single crystals of the iron-arsenide superconductor BaFe2(As1−xPx)2, x=0.33. The effect of disorder on the low temperature behavior of the London penetration depth, λ(T) and transition temperature, Tc, was investigated. In near-optimal doped samples with Tc ∼ 29 K, signatures of a superconducting gap with nodes were observed. Contrary to previous reports on electron irradiated crystals, we do not see a disorder driven lifting of accidental nodes, and we observe that proton induced defects are weaker pairbreakers than electron induced defects. We attribute our findings to anisotropic electron scattering caused by proton irradiation defects.