The influence of radiation induced atomic disorder on the superconducting properties of Nb3Sn

After high dose neutron or ion irradiation of Nb3Sn several authors have observed a marked depression of Tsub(c), Hsub(c2) and Jsub(c). By a model calculation within the framework of the linear chain model it is shown that these effects might be explained by the decrease of the electron density of states at the Fermi level, Esub(F), due to radiation induced atomic disorder. The influence of atomic disorder on Esub(F), Tsub(c), and on the intrinsic superconducting material parameters lambda, xi, kappa, Hsub(c), Hsub(c2) is calculated numerically and the results are compared with experiments. The depression of the critical current density for doses phi>2x1018n/cm2, in spite of a softening of the elastic properties of the flux line lattice after irradiation, is shown to be due to a drastic decrease of the elementary pinning forces. (Auth.)