The structure analyses of α″-Fe16N2 sputtered films were made by using XRD, TEM, CEM and EPMA. The following results were verified: (1) the lattice constants, a and c, of the α″-Fe16N2 phase in the sputtered film were found to be the same as those of bulk α″-Fe16N2; (2) the film consists of highly oriented single-crystal grains with diameter of about 100 Å; and (3) the volume fraction of (α″ + α′)-Fe16N2 phase in the annealed film was found to be 71-82%. The value of the saturation magnetization of the α″-Fe16N2 phase was discussed by assuming N site ordering in the α′-martensite. The results revealed that no strong correlation between the N-site ordering in α′-phase and the magnetic moment is found and that the value of the saturation magnetization of the α″-Fe16N2 phase at RT is concluded to be no more than 240 emu/g.
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