Generally, MgB2 wires possess a niobium diffusion barrier to prevent an unacceptable reaction between magnesium powder and copper stabilizer. However, given that niobium is costly, extensive studies were conducted to replace the niobium diffusion barrier with iron. Nevertheless, the MgB2 wire with iron diffusion barrier is not yet practically applied to magnetic resonance imaging magnets because the magnetization of ferromagnetic iron may lead to poor uniformity of the magnetic field distribution of the magnet. In this study, the magnetic field characteristics of solenoid magnet wound with MgB2 wire possessing an iron diffusion barrier were examined to investigate the iron barrier effects on the field homogeneity of magnets. In addition, the magnetic field drift of the magnet in a persistent current mode operation was presented. For a comparative analysis, an MgB2 magnet that utilizes conventional wires with a niobium diffusion barrier was also assessed.
This work was supported by the Materials and Components Technology Development Program of KEIT [10053590, Development of MgB2 wire and coil with a high critical current and long length for superconducting medical·electric power equipment].