Synthesis and magnetic moment of α´ and γ´-Fe-N phases with various unit-cell volume

α´ and γ´ phases of Fe-N are synthesized with various unit cell volume using multilayer fabrication technique. The volume effect on magnetic moment and Curie temperature (T_c) for these phases is examined. In the case of α´-Fe-N, the magnetic moment and the exchange integral, which corresponds to T_c, decrease with increasing unit cell volume. For γ´-F-N, the magnetic moment and exchange integral take a maximum near the volume of bulk Fe₄N. From these results, both the magnetic moment and T_c is expected to enhance when the unit-cell volume of the γ´ phase is larger than that of bulk Fe₄N without leading to structural instability.