“…1-8 Doping with different metals, 9,10 variation of stoichiometry, 11 and nonsuperconducting phase precipitation 12 are recent examples of the chemical tuning of superconducting materials. 14 Alternative synthetic routes 13,15 and postsynthesis treatments, 16 fabrication of dense wires, 17 pellets, 16 and tapes, 18 annealing in Mg vapor, 19 doping with Na, 20 Co, Fe, 21 Cu, or Ag, 10 introduction of SiC nanoparticles, 22 Ag powder, 23 Ti precipitates, 24 synthesis of MgB 2 /Mg nanocomposites, 25 intralayer carbon substitution 11,26 have all been reported. 1, 6,13 Various techniques to control pinning properties of MgB 2 have been suggested.…”