A first review was presented of the main normal and superconducting state properties of magnesium diboride. It had already been fabricated in bulk, single-crystal, thin-film, tape and wire forms. The largest critical current densities (greater than 10MA/cm2) and critical fields (40T) were found for thin films. The anisotropy ratio, deduced from upper critical field measurements, had yet to be resolved; since a wide range of values (1.2 to 9) had been reported. Also, there was no consensus on the existence of a single anisotropic or double energy gap.

Review of the Superconducting Properties of MgB2. C.Buzea, T.Yamashita: Superconductor Science and Technology, 2001, 14, R115-46