  We report on significant flux pinning enhancement in MgB2/Fe tapes that has
been easily obtained by a simple and cheap route using acetone as both an
efficient ball-milling medium and liquid additive through the in situ method.
Results showed that the highly reactive C released from the decomposition of
the acetone substituted into B sites, accompanied by the grain refinement
effect due to the acetone doping. At 4.2 K, the transport Jc for the 5 wt %
acetone doped tapes sintered at 700C reached up to 2.4x10^4 A/cm^2 at 10 T,
which is even higher than that of the nano-C added samples heated at 900C.
