Transport properties of powder-in-tube processed MgB2 tapes

Nickel-sheathed magnesium diboride superconducting tapes have been fabricated by the powder-in-tube method from reacted commercially available powders. At 4.2 K and self field, a transport current density value j(c) of 10(5) A/cm(2) has been reached over long portions of unsintered monofilamentary tapes. The irreversibility lines both for a magnetic field oriented parallel and perpendicular to the MgB2 superconducting tape have been determined by magneto resistance measurements, showing some degree of anisotropy. These data are consistent with the X-ray diffraction observation of a slight texturing process of the MgB2 grains occurring during the cold working, procedure.