Superconducting and normal-state properties of vanadium nitride

The near stoichiometric compound ${\mathrm{VN}}_x$ with NaCl structure has been prepared in two different forms: (1) by reacting V foils directly with pure ${\mathrm{N}}_2$, and (2) by reactive sputtering. The magnetic susceptibility and electrical resistivity data of ${\mathrm{VN}}_x$ are consistent with the spin-fluctuation view proposed for this material. Superconducting tunneling results indicate that ${\mathrm{VN}}_x$ is a strong-coupled superconductor with $\frac{2\Delta }{{\kappa }_B{T}_c}\simeq 3.92$.