Influence of neutron irradiation damage on the equilibrium properties of the polycrystalline Bi1.8Pb0.3Sr2Ca2Cu3O10 superconductor

Studies of the magnetization of the polycrystalline Bi1.8Pb0.3Sr2Ca2Cu3O10 superconductor revealed substantial changes in several properties, arising from moderate levels of damage from neutron irradiation. In addition to the expected increases in current density (as evidenced by increased magnetic hysteresis), analysis of the equilibrium magnetization revealed significant increases in several more fundamental properties, including the upper critical magnetic field Hc2 and the London penetration depth λab; these increased by 30 and 15 %, respectively, following irradiation with 0.8×1017 n/cm2, with still larger increases at a higher fluence. However, the most intrinsic properties, specifically the thermodynamic critical field Hc and the superconductive condensation energy Fc, were unchanged at the highest neutron fluence used, 2.4×1017 n/cm2. We attribute the changes in fundamental properties to mean-free-path effects, via increased scattering of conduction electrons.