Pinning forces in deuteron-irradiated A15-superconductors

It is shown, that in monofilament samples of varying Nb3Sn-layer thickness and different reaction temperatures irradiated by 50 MeV-deuterons at low temperatures the observed changes in critical current density, j(c), may be separated as caused by density of pinning centers as well as by the upper critical field, B(c2), and transition temperature, T(c). At low fluences the enhancement in volume pinning force j(c) x B as function of dose is just less than linear and dependent on the T(c)-value before irradiation. At high fluences (> 1018 cm-2), the degradation of T(c) and B(c2) is dominant and the decrease in j(c) may be understood as a consequence. Comparing specific pinning forces per grain boundary and irradiation pinning center one finds both to be comparable in magnitude and showing the same response to radiation damage, which may be caused by similar flux pinning interactions. (orig./HP) 891 HP/orig.- 892 BRE