Composition Controls Phase Purity, Texture, and Transport in Layered FeMN₂ Nitride Thin Films
Layered ternary iron nitrides FeWN₂ and FeMoN₂ can be synthesized as thin films via reactive sputtering followed by NH₃ annealing, but their structural and electronic responses to composition variation are fundamentally different. FeWN₂ tolerates a wide composition range with high phase purity and stable low resistivity (~1 mΩ·cm), consistent with simple cation substitution, while FeMoN₂ achieves phase purity only at Fe-poor compositions and exhibits a sharp resistivity maximum near stoichiometry. Crystallographic texture also evolves strongly with composition in both systems, transitioning from out-of-plane fiber texture in Fe-rich films to in-plane orientation near stoichiometry in FeWN₂, revealing tight coupling between composition, microstructure, and electronic/magnetic properties.