An experimental study of the effect of MgO content in the MgB2 powder used for ex situ composite wires was carried out. Two single-core MgB2/Fe/Cu wires were made using commercial MgB2 powders containing different fractions of MgO. Critical temperature and critical currents of as-deformed and heat-treated wires were measured. The differences between the wires were correlated with the MgO content. It was found that by increasing the amount of MgO, the inter-grain connectivity worsens, but well distributed and low size MgO particles improve flux pinning.

The Role of MgO Content in ex situ MgB2 Wires. P.Kovác, I.Husek, T.Melisek, J.C.Grivel, W.Pachla, V.Strbík, R.Diduszko, J.Homeyer, N.H.Andersen: Superconductor Science and Technology, 2004, 17, L41-6