Single-core MgB2 composite tapes were prepared by an in situ process with various metallic sheaths (Fe, Ta, Nb). Normal particles (10wt% of W and SiC) were also added to the Nb-sheathed samples. Critical currents measured in parallel and perpendicular field directions, and the angular dependences of the critical currents, revealed a JC anisotropy which was influenced by the sheath material used and by the presence of normal particles. The observed differences were attributed to the coexistence of 2 dominant effects influencing JC(B) characteristics: the texture of MgB2 close to the interface area and the effective pinning (additions). A comparison of in situ and ex situ results indicated that final c-axis grain alignment was more important for the in situ process.

IC Anisotropy of in situ Made MgB2 Tapes. P.Kovác, T.Melisek, I.Husek: Superconductor Science and Technology, 2005, 18, L45-8