Rational design of MgB2 conductors toward practical applications

• Performance of MgB2 conductors can compete and exceed that of conventional Nb–Ti.
• We report on research progress that has been made on developing MgB2 conductors.
• Chemical doping has proved to be the most effective way to improve current carrying capacity.
• The n-value is a critical index for optimization of the design of superconducting MRI magnet.
• MRI magnet is made possible with a superconducting joint.

We report the research progress that has been made on developing rational MgB2 superconducting conductors toward practical applications. Owing to the poor performance of the critical current density (Jc) of bare MgB2, various techniques have been developed to overcome this obstacle. Among these, chemical doping has proved to be the most effective way to enhance the superconducting properties, such as Jc and the irreversibility field (Birr). More than a hundred different forms of dopants have been investigated over the past 13 years. Among these, the most effective dopants have been identified to be silicon carbide, carbon, and malic acid. The best results, Birr of 22 T and Jc of 40,000 A cm−2 at 4.2 K and 10 T, have been reported for malic acid treated MgB2 conductors, which have matched the benchmark performance of commercial low temperature superconductor wire such as Nb–Ti. This work will review and discuss the progress on MgB2 conductor development over the past few years at the University of Wollongong and Hyper Tech Research, Inc.