An investigation was made of the electrical transport properties of 2 wires containing four MgB2 filaments in an Fe matrix, made by using an ex situ process. The 2 wires differed in their final treatment. While only mechanical deformation steps were applied to one of them (wire A), the other (wire B) was annealed in an Ar atmosphere in order to achieve sintering of the powder grains. Critical currents were measured by using the transport method, at temperatures ranging from 4.2 to 30K, and in magnetic fields up to 8T. Due to the sintering step, the critical currents and pinning energies of wire B increased strongly with respect to wire A. Analysis of the R(T) curves and current–voltage characteristics revealed that the irreversibility line was affected by the sintering process. An explanation of the observed behaviors was offered in terms of the differing activation volumes for pinning energies.

Influence of the Sintering Process on Critical Currents, Irreversibility Lines and Pinning Energies in Multifilamentary MgB2 Wires. P.Fabbricatore, M.Greco, R.Musenich, P.Kovác, I.Hušek, F.Gömöry: Superconductor Science and Technology, 2003, 16, 364-70