  Multifilamentary MgB2/Fe wires and tapes with high transport critical current
densities have been fabricated using a straightforward powder-in-tube (PIT)
process. After annealing, we measured transport jc values up to 1.1 * 105 A/cm2
at 4.2 K and in a field of 2 T in a MgB2/Fe square wire with 7 filaments
fabricated by two-axial rolling, and up to 5 * 104 A/cm2 at 4.2 K in 1 T in a
MgB2/Fe tape with 7 filaments. For higher currents these multifilamentary wires
and tapes quenched due to insufficient thermal stability of filaments. Both the
processing routes and deformation methods were found to be important factors
for fabricating multifilamentary MgB2 wires and tapes with high transport jc
values.
