Preparation and properties of unsintered MgB2 superconducting tapes

The Powder-In-Tube process has been employed to fabricate long Nickel-sheathed MgB2 superconducting tapes from reacted commercially available powders. The cold working processing of the Nickel-based tape allows to reach a high degree of compaction of the MgB2 powders inside the sheath and therefore, thanks to the large superconducting coherence length, a considerable current flow is achievable even in unsintered conductors. At 4.2 K and self field, a transport current density of 10(5) A/cm(2) has been reached over long portions of unsintered monofilamentary tapes. The irreversibility line of the superconducting tape has been determined by magnetoresistance measurements as well by the Kramer plot of the j(c)(B,T) data, showing that the strong field dependence of j(c), especially at temperatures above 10 K and for magnetic fields larger than 1 Tesla, is dominated by the low intrinsic pinning proper-ties of the MgB2 phase.