Helical windings of Fe-sheathed MgB2 wires with different dimensions were fabricated by a wind-and-react process. Wires with a cross-sectional area of 1mm2 and 20% superconductor core were made using the powder-in-tube method and ultra-fine starting precursors. Very good grain connectivity as well as high core density was obtained by using this method. At 20K and self-field, the critical current of a coil with an ID of 12mm and 12 turns was 360A, which was equivalent to a JC of 1.8 x 105A/cm2. At a 6T external magnetic field and 4.2K, a coil with an ID of 140mm and 10 turns possessed a JC of 104A/cm2. These results were a step towards the application of MgB2 wires in the temperature range of 20–30K and high magnetic fields.

Transport Critical Current on Fe-Sheathed MgB2 Coils. H.Fang, P.T.Putman, S.Padmanabhan, Y.X.Zhou, K.Salama: Superconductor Science and Technology, 2004, 17, 717-20