Epitaxial single crystal Fe₁₆N₂ films grown by facing targets sputtering

α″-Fe₁₆N₂ single crystal films can be prepared successfully by facing targets sputtering directly onto NaCl(100) substrates in a mixture of argon and nitrogen gases. Both x-ray diffractometer and transmission electron microscope are employed to characterize the crystal structure of the films. The perfect electron diffraction patterns of α″-Fe₁₆N₂ single crystal in [111], [011], and [001] directions can be distinctly observed by double tilting. These patterns confirm that the crystal structure of the films corresponds to a body-centered tetragonal (bct) lattice with the parameters of a=b=5.72 Å and c=6.29 Å . The x-ray diffraction patterns show that α″-Fe₁₆N₂ epitaxially grows on the NaCl(100) substrate with an orientation relationship α″-Fe₁₆N₂(001)∥NaCl(001) and α″-Fe₁₆N₂[100]∥NaCl[100]. The saturation magnetization of the Fe₁₆N₂ films is around 2100-2300 emu/cc, which agrees well with the value reported by Sugita et al..