Insertion versus Growth of Magnetic Nanoparticles in MgB<sub>2</sub> Superconducting Composites

Abstract

MgB2-based superconducting composites with magnetic nanoparticles were fabricated by spark plasma sintering technique. Two methods have been used to create nanoparticles within MgB2 matrix: i) direct insertion of passivated magnetic nanoparticles; ii) growth of magnetic nanoparticles by thermolysis of polymers or metallo-organic precursors. These composites display an enhanced critical current density due to the additional magnetic pinning generated by the magnetic interaction with the flux lines.