Comparison of Critical Current Density in ${\rm MgB}_{2}$ With Different Boron Sources and Nano-Particle Dopant Additions

MgB₂ strands with various dopants and various types of B were characterized using transport J_c. In particular, amorphous, nanocrystalline, and plasma spray processed B powder based samples were compared. In a number of cases, various nanoparticle additions were then made to improve the properties with the given strand and B powder type. SiC, TiC, Ag nano ceramics were purchased from a commercial source and were then mixed into the wire during the milling stage. In one case, Malic acid was the dopant, and added at this milling stage. The doped powders were then dispensed into monofilamentary wires in which a Nb-lined monel sheath construction was used. Transport J_c measurements were performed on all samples under a variety of magnetic fields and in some cases temperatures. These results were then compared to our previous results with and without dopants.