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

We report transport, electromechanical, and structural properties of single core MgB2/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 MgB2 structure in the center and a dense circular MgB2 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 MgB2 structure shared the applied current and indirectly behaved as an internal stabilizer against quench damage at high applied currents.