paper

Effects of Neutron Irradiation on Carbon Doped MgB2 Wire Segments

arXiv:cond-mat/0507275 · doi:10.1088/0953-2048/19/6/024

Abstract

We have studied the evolution of superconducting and normal state properties of neutron irradiated Mg(B $_{.962}$ C $_{.038}$ ) $_{2}$ wire segments as a function of post exposure annealing time and temperature. The initial fluence fully suppressed superconductivity and resulted in an anisotropic expansion of the unit cell. Superconductivity was restored by post-exposure annealing. The upper critical field, H $_{c 2}$ (T=0), approximately scales with T $_{c}$ starting with an undamaged T $_{c}$ near 37 K and H $_{c 2}$ (T=0) near 32 T. Up to an annealing temperature of 400 $^{o}$ C the recovery of T $_{c}$ tends to coincide with a decrease in the normal state resistivity and a systematic recovery of the lattice parameters. Above 400 $^{o}$ C a decrease in order along the c- direction coincides with an increase in resistivity, but no apparent change in the evolution of T $_{c}$ and H $_{c 2}$ . To first order, it appears that carbon doping and neutron damaging effect the superconducting properties of MgB $_{2}$ independently.