Anisotropy of Jc in ex situ MgB2/Fe monofilamentary tapes

The anisotropy of the critical current density of Fe-sheathed ex situ MgB₂ monofilamentary tapes has been measured at various magnetic fields and temperatures and has been found to be influenced by the particle size of the starting material. Already reacted powders were milled in order to obtain different starting particle sizes. In order to understand the origin of the anisotropy, we have undertaken an X-ray study on the degree of texturing in the filaments after mechanical removal of the Fe sheath. The degree of texturing of the filaments at the interface Fe/MgB₂ and at the center of the filaments has been determined. A moderate texture has been found, being slightly higher at the interface.