Superconducting Performance of Ex-situ SiC Doped MgB 2 Monofilamentary Tapes

The superconducting performance of the ex-situ SiC doped MgB 2 monofilamentary tapes are reported. Polycrystalline powders of MgB 2 doped with 5 and 10 wt% SiC were synthesized by a conventional solid-state reaction route and characterized for their superconducting performances. It was found that the superconducting parameters viz., upper critical field ( H c2 ), irreversibility field ( H irr ) and critical current density ( J c ) were improved significantly with SiC addition. It was also found that relatively lower synthesis temperature resulted in further improved superconducting parameters in comparison to higher synthesis temperature. Thus, synthesized powders are used for the fabrication of ex-situ powder-in-tube (PIT) monofilamentary tapes. The superconducting performance in terms of critical current density ( J c ), being determined from both magnetization ( J cm ) and transport ( J ct ) measurements, was improved significantly. In particular, the SiC doped MgB 2 tapes (fabricated using 700 °C heat treated bulk powder) exhibited the transport J ct of nearly 10 4 A/cm 2 under applied fields of as high as 7 Tesla. Further, it was found that the J ct anisotropy decreases significantly for SiC doped tapes. Disorder due to substitution of C at B site being created from broken SiC and the presence of nano SiC respectively in SiC added ex-situ MgB 2 tapes was responsible for decreased anisotropy and improved J c ( H ) performance.