Improved Synthesis of Superconducting Carbon-Doped MgB2 Using a Biopolymer for Simultaneous Crystallite Size Control and Chemical Reduction

This study represents a key evolution in the synthesis of the superconductor MgB2, as it is the first to demonstrate that templated synthesis can be carried out successfully without a sealed reaction vessel. This is possible owing to the strong chelating ability of the biopolymer dextran, whose morphological complexity effectively cocoons the reaction, preventing oxygen ingress. This synthetic protocol demonstrates that not only can this important material be synthesized as nanoparticles but that, as the morphological template is calcined, it effectively carbon-dopes the superconducting phase, thereby improving the critical current density by a factor of five.