Effect of the neutron irradiation of the high temperature superconductor (Cu,C)Ba2Can-1CunO2n+4-delta (n=3, 4 and 5)

The critical current density J(c) is measured for the neutron irradiated po lycrystalline samples of (Cu1-xCx) Ba2Can-1CunO2n+4-delta (n = 3, 4 and 5; hereafter described as (Cu,C)-1223, (Cu,C)-1234 and (Cu,C)-1245) family. J( c) was evaluated by the Bean model from M-H curves. J(c) decreases from 3.0 x 10(5) to 1.5 x 10(5) A/cm(2) (0.5 T, 77 K) for (Cu,C)-1223 and increases from 5.8 x 10(4) to 8.0 x 10(5) A/cm(2) (1 T, 77 K) for (Cu,C)-1234 and fr om 1.7 x 10(3) to 2.0 x 10(4) A/cm(2) (0.5 T, 77 K) for (Cu,C)-1245 after i rradiation with a fluence of 1 x 10(17) cm(-2). Superconducting transition temperature T-c of these compounds decreased slightly (similar to1 K). The irreversibility field H-irr increased toward higher field except for (Cu,C) -1223. These results show that (Cu,C)-1234 is a promising practical materia l for high J(c) and high H-irr. (C) 2001 Elsevier Science B.V. All rights r eserved.