Synthesis and characterization of superconducting nanocrystalline niobium nitride

Nanocrystalline niobium nitride (NbN _0.9) was successfully synthesized at 600 ° through a solid-state reaction. The synthesis was carried out in an autoclave by using NbCl ₅ and NaN ₃ as the reactants. The X-ray powder diffraction pattern indicates the formation of cubic NbN _0.9. Transmission electron microscopy images show that typical NbN _0.9 crystallites are composed of uniform particles with an average size of about 30 nm and nanorod crystallites with a typical size of about 40 × 2500 nm. Magnetic measurements exhibited that a superconducting transition occurred at 15.4 K for the NbN _0.9 product.