Transport and structural properties of MgB₂/Fe wires produced by redesigning internal Mg diffusion process

Abstract We report transport, electromechanical, and structural properties of single core MgB 2 /Fe wire produced using a new fabrication method, called designed internal Mg diffusion (IMD) process, which relies on the use of non-stoichiometric Mg + B pellets with excess Mg in place of a central Mg rod used in the standard IMD method. Structural analysis revealed the successful formation of a porous MgB 2 structure in the center and a dense circular MgB 2 layer surrounding this structure in the designed-IMD wire. Fast transport I – V measurements showed that the designed IMD method increased engineering critical current density ( J e ) up to twice that of the IMD wires in self-field. The central porous MgB 2 structure shared the applied current and indirectly behaved as an internal stabilizer against quench damage at high applied currents.