Current Density and Quench Behavior of MgB 2 /Ga Composite Wires

Magnesium diboride (MgB 2 ) is a promising superconductor for many technical applications. Sufficient current densities at required magnetic fields, moderate operational temperature, low raw materials' cost, and an economical manufacturing process have enabled commercial development of MgB 2 wires. Reacted MgB 2 , however, is brittle, and applications involving coils and windings with small bend radii are therefore difficult to implement. Furthermore, improvements in the critical current density are needed to expand the range of potential applications. Here, we report on the electrical behavior of novel MgB 2 /Ga composite wires produced such that the proximity effect enhances connectivity, allowing the high-temperature anneal typically required for in situ and ex situ MgB 2 wires to be eliminated. Elimination of the high-temperature anneal simplifies MgB 2 manufacturing and has the potential to create a wire that is more tolerant of bending. Here, we present critical current density and quench propagation results for MgB 2 /Ga composite wires sheathed in Cu.