engleski

Critical currents and vortex pinning in U/n treated Bi2223/Ag tapes

Critical currents J(c)(T, B) for virgin and four U-235 doped Bi2223/Ag tapes irradiated with thermal neutrons (U/n treated) were measured in the temperature range T greater than or equal to 50 K and magnetic field B less than or equal to 1 T. Below 97 K vortex pinning in U/n treated tapes increases with matching field B-phi, as evidenced by a weaker B dependence of J(c) on increasing B-phi. Hence, the field B-max (F-pmax = J(c)B(max)) and the irreversibility field B-irr(F-p --> 0) of U/n treated tapes are enhanced compared to those for virgin tape. Since the rate of the enhancement of B-max and B-irr with B-phi depends on T, one can tune the maximum enhancement at desired T.

flux pinning; uranium doping; neutron irradiation

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