There is a gr eat interest in obtaining epitaxial α″ nitride phase of iron because of their special ferromagnetic properties. α″ Fe 16 N 2 thin films have been prep ared by facing target sputtering (FTS) onto NaCl (001) substrates in a mixture of argon(Ar) and N 2 gases. The base pressure was 6×10 -5 Pa. During sput tering, the partial pressures of Ar and N 2 gases were kept constant at 0.3 Pa and 0.05 Pa respectively. The deposition rate was about 0.2 nm/s. The substrate temperature was held at about 100 ℃. Annealing of the films was sequentially ca rried out at 150 ℃ for 1 h in vacuum ( at least 10 -4 Pa ) to obtain α″ phase. Transmission electron microscope (TEM) observations and X ray diffract ion (XRD) patterns showed that the α″ Fe 16 N 2 epitaxially grew on the NaCl substrates. It was found that the arrangement of the SAD patterns exhibits perfect symmetries.By using super lattice reflections, the lattice constants a=b=(5.71±0.02)×10 -1 nm and c=(6.30±0.04) ×10 -1 nm of the α″ phase with a body centered tetragonal (BCT) structu re were determined, which was very close to the results obtained by Jack (a=b= 5.72×10 -1 nm, c= 6.29×10 -1 nm). The X ray diffraction patterns and the selected area diffraction patterns showed t hat α″ Fe 16 N 2 epitaxially grew on the NaCl (001) substrate with orien tation relationships α″ Fe 16 N 2 (001) ‖NaCl (001),α″ Fe 16 N 2 ‖NaCl .
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