Recent progress in MgB₂ superconducting joint technology

Magnesium diboride (MgB₂) magnets have the potential to be the next-generation liquid-helium-free magnet for magnetic resonance imaging (MRI) application due to their relatively high superconducting transition temperature, high current density and low raw material cost compared with current commercial niobium-titanium (Nb-Ti) magnets. A typical superconducting magnet includes several coils. To produce an ultra-stable magnetic field for imaging in MRI, a superconducting electromagnet operating in a persistent mode is crucial. Superconducting coils of the electromagnet in MRI are short-circuited to operate in the persistent mode by connecting coils with superconducting joints. Persistent joints have been demonstrated for in-situ and ex-situ wires of both mono- and multi-filamentary structures, made predominantly by PIT techniques similar to those used in wire production. To realise further engagement of MgB₂ in MRI applications, enhancing the performance of MgB₂ superconducting joints is essential. This literature review summarises research and development on MgB₂ superconducting joining technology.