Electronic, magnetic and elastic properties of γ-Fe4X (X=B/C/N) from density functional theory calculations

The crystal structure and elastic and electronic properties of γ-Fe4B were predicted using density functional theory calculations. In view of the formation energy, the phase stability increases from γ-Fe4B, γ-Fe4C to γ-Fe4N. It is confirmed that the bonds of γ-Fe4X (X=B/C/N) are complex mixtures of metallic, covalent and ionic characters. The ionicity of FeX increases from FeB, FeC to FeN in γ-Fe4X (X=B/C/N). The magnetic moments of γ-Fe4X (X=B/C/N) are mainly contributed by 3d electrons of metal atoms. For γ-Fe4B, the values of Fe Ms are 3.118 and 2.024 μB for FeI and FeII, respectively. For γ-Fe4C, the values of Fe Ms are 3.135 and 1.696 μB for FeI and FeII, respectively. For γ-Fe4N, the values of Fe Ms are 2.972 and 2.307 μB for FeI and FeII, respectively. The Debye temperatures of γ-Fe4X (X=B/C/N) are predicted as 366, 500 and 477 K.

► The bonds of γ-Fe4X (X=B/C/N) are the complex mixtures of metallic, covalent and ionic characters. ► The ionicity of FeX increases from FeB, FeC to FeN in γ-Fe4X (X=B/C/N). ► The magnetic moments of γ-Fe4X (X=B/C/N) are mainly contributed by 3d electrons of metal atoms. ► The Debye temperatures of γ-Fe4X (X=B/C/N) are predicted as 366, 500 and 477 K.