Improvement in the J_c−B Characteristics of Ex-Situ MgB₂ Tape With SiC Addition

The utilization of MgB₂ powder obtained from the core of in-situ MgB₂ tape improves the high magnetic field J_c - B performance of Fe-sheathed MgB₂ tape fabricated via an ex-situ powder-in-tube (PIT) technique. This work reveals a further improvement by means of the addition of SiC nano particle. The highest J_c at 4.2 K of the tape have a values of 4.6 x 10³ A/cm² (I_c ap26 A at 12 T) and 9.7 x 10³ A/cm² (I_c ap 54 A at 10 T) for the tape with 10 mol% SiC post-annealed at 700deg C. These values are believed to be the highest known J_c values of ex-situ MgB₂ tape. However, they were lower than the values of in-situ MgB₂ tape with 10 mol% SiC (J_c 6.3 X 103 A/cm² ap 43 A at 12 T and 1.3 x 104 A/cm² : I_c ap 88 A at 10 T). The reason for the poorer J_c -B performance of the ex-situ MgB₂ tape is thought to be due to a lower B_irr and poorer grain connectivity.