Improvement in the $J_{\rm c}-B$ Characteristics of Ex-Situ ${\rm MgB}_{2}$ Tape With SiC Addition

The utilization of MgB
₂
powder obtained from the core of in-situ MgB
₂
tape improves the high magnetic field J
_c
- B performance of Fe-sheathed MgB
₂
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 10
³
A/cm
²
(I
_c
ap26 A at 12 T) and 9.7 x 10
³
A/cm
²
(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 MgB
₂
tape. However, they were lower than the values of in-situ MgB
₂
tape with 10 mol% SiC (J
_c
6.3 X 103 A/cm
²
ap 43 A at 12 T and 1.3 x 104 A/cm
²
: I
_c
ap 88 A at 10 T). The reason for the poorer J
_c
-B performance of the ex-situ MgB
₂
tape is thought to be due to a lower B
_irr
and poorer grain connectivity.