Transport critical current densities and n-values were measured at 4.2K in fields up to 15T on 7-, 19- and 37-stack multifilamentary MgB2 strands made by using an in situ route. Some strands included SiC additions (particle size ~30nm) while, in others, Mg-rich compositions were used. Two basic multifilamentary variants were measured; the first had Nb filamentary barriers, the second had Fe filamentary barriers. All of the samples incorporated a stabilizer in the form of Cu. Simple 1-step heat treatments (700 to 800C, 10 to 30min) were used. Transport critical current densities of 1.75 x 105A/cm2 were seen at 4.2K and 5T in 37-stack strands. One-metre segments of strand were also measured at 4.2K. These exhibited critical current densities of 6 x 105A/cm2 in zero field. The magnetic JC values of 37-stack strands were measured. These measurements showed that the intrinsic JC of the material attained 106A/cm2 at 20K.

Multifilamentary in situ Route Cu-Stabilized MgB2 Strands. M.D.Sumption, M.Bhatia, X.Wu, M.Rindfleisch, M.Tomsic, E.W.Collings: Superconductor Science and Technology, 2005, 18, 730-4