D. Marinaro et al., The effects of uranium doping and thermal neutron irradiation on the pinning properties of Ag/Bi-2223 tapes, PHYSICA C, 341, 2000, pp. 1119-1120
Ag/Bi-2223 multifilamentary tapes doped with small quantities of UO4 powder
were prepared by the powder-in-tube process. Thermal-neutron irradiation o
f these tapes induces fission of the U-235 atoms, with the resulting fissio
n fragments creating randomly splayed defects. An observed increase in J(c)
after irradiation as well as a shift in the irreversibility line to higher
fields, in comparison to nondoped samples, implies an improvement in the f
lux pinning of the tapes as a result of this process. Dynamic magnetization
relaxation measurements were conducted to elucidate the behaviour of the e
ffective activation energy (U-eff) as a function of current density. Change
s in the activation energy after irradiation are examined and related to ch
anges in the pinning potential of the tapes.