Superconductivity ofB1-MoN films annealed under high pressure

B1-phase MoN films, prepared by sputtering, are annealed under a pressure of 6 GPa at temperatures between 600 and 1100 °C for 8 h. The B1-phase MoN is converted mainly to hexagonal-phase and partly to tetragonal-phase ${\mathrm{Mo}}_2$N when annealed at temperatures above 750 °C. A residual phase was observed only at an annealing temperature of 600 °C. The $T_{\mathrm{co}}$ (the onset of $T_c$) of 1000 °C-annealed films was 14.9 K; this is the maximum value found in the literature for the Mo-N system.