Significant enhancement of the in-field critical current density of the MgB_2 superconductor through codoping of nano-TiC with nano-SiC

摘要

Nanoparticles of two carbides, SiC and TiC, having different reactivities with the Mg/B are doped into the MgB_2 system. These carbides are added in mono-and codoping conditions through the in situ solid state reaction, and the structural and superconducting properties are studied. The results show distinct modifications in the structural and superconducting properties by the two dopants. SiC causes considerable C substitution at the B site and the formation of intragrain inclusions, whereas TiC remains unreacted and does not cause any substitution. The codoped samples show significantly enhanced J_C(H) performance compared to the undoped and monodoped samples. Compared to the undoped sample, the enhancement of J_C is more than two orders of magnitude at 15 K for fields >7 T for the best sample. The results of J_C(H) performance of the samples are discussed. (Some figures in this article are in colour only in the electronic version)