Phase formation and transport properties of vapor-solid reacted AIMI MgB₂ superconductors

Vapor-solid reactions were applied to monofilament and 6-filament AIMI MgB₂ wires. A layer J of ~ 10⁵ A cm^-2 was achieved by the generation of a highly dense MgB₂ layer after reaction at 625 °C for 8 to 16 h. It was found that the critical current, I , and engineering current density, J , reached maximum values of 92.3 A and 1.15 × 10⁴ A cm^-2 at 4.2 K, 10 T when the multifilament AIMI wire was heat-treated at 625 °C, for 14 h. Transport I s were also measured at 10-20 K for the wire heat-treated at 625 °C for 16 h. Phase formation investigations suggested that even better performance of I and J could be attained in multifilamentary AIMI MgB₂ wires after further conductor optimization.