Interpretation of the Magnetic and Crystallographic Properties of Several Iron, Nickel, and Iron-Nickel Nitrides

The saturation moment at 4°K and the room-temperature structure of the following nitrides have been examined: ${\mathrm{Fe}}_{\text{4−x}}{\mathrm{Ni}}_x\mathrm{N}$ with $\text{0\hspace{0.17em}≤\hspace{0.17em}x\hspace{0.17em}≤\hspace{0.17em}3}$ (${\mathrm{Fe}}_4\mathrm{N}$ -type structure); tetragonal, ordered FeNiN; hexagonal ${\mathrm{Fe}}_{\text{3−y}}\mathrm{N}$ with $\text{0\hspace{0.17em}<\hspace{0.17em}y\hspace{0.17em}<\hspace{0.17em}1}$ ; hexagonal ${\mathrm{Ni}}_3{\mathrm{N}}_{\text{1.16}}$ ; and orthorhombic ${\mathrm{Fe}}_2\mathrm{N}$ . The atomic ordering, nitrogen solubility, and atomic moments of the system ${\mathrm{Fe}}_{\text{4−x}}{\mathrm{Ni}}_x\mathrm{N}$ are interpreted from a model of the band structure of the f.c.c. transition elements of the first long period in which it is explicitly assumed that the crystalline fields split the d bands into separable components.