The current transfer length in composite MgB2 wires with different metallic sheaths and filament numbers was analysed. The electric potential gradient along the wire in the vicinity of the current contact was monitored as a function of transport current in various external magnetic fields up to 14 T. In all samples the characteristic current transfer length is of the order of a millimetre, varying with detailed sheath composition in the range 0.35–2 mm. For the wires with a clear reaction layer at the filament/matrix interface, the electrical resistivity of the material constituting such a barrier was estimated.

Stabilized four-filament in situ MgB2/Ti/Cu/Monel composite wire was produced by the rectangular wire-in-tube (RWIT) technique. 10 wt% of nanosize SiC was added into the Mg–B powder mixture, which was packed into the Ti/Cu and Monel tubes, respectively. The assembled composite was two-axially rolled into wire and/or tape form and sintered at temperatures of 650–850 °C/0.5 h. Stabilized MgB2 wire with Ti barrier is studied in terms of field-dependent transport critical current density, effects of filament size reduction and thermal stability.

During the past few years the superconducting properties of mono and multifilamentary MgB 2 wires and tapes have been improved considerably. However, not much work has yet been done to cabling procedures that are well known for classical low temperature superconductors, despite the fact that MgB 2 conductors can easily be produced in a round-shape geometry. Nowadays, it is a challenge to fabricate MgB 2 -based cables suitable, for instance, for magnet technology or power transmission.This paper presents a technique for cable production and studies the transport properties of different sub-size MgB 2 cables, fabricated from mechanically and electrically-stabilized thin MgB 2 strands capable of carrying high critical currents. The cables vary in matrix composition and in the final design. It is shown here that it is possible to construct cables which do not show degradation for the critical current. Furthermore, the possibility of using a very small twist pitch (∼5 mm) in the cables compared to their outer diameter (∼1 mm) indicates a promising future for MgB 2 superconductors.