Synthesis of Layered Ternary Nitride FeWN₂ and FeMoN₂ Thin Films by Combinatorial Sputtering

Ternary transition metal nitrides are an emerging class of materials for exploring quantum phenomena and offer a great degree of tunability by modulating the cation ratio. Among them, ABN₂-type nitrides exhibit a self-assembled layered structure causing a variety of exotic quantum properties, as seen in similar layered oxides. We report on the successful synthesis of FeWN₂ and FeMoN₂ thin films using a combinatorial reactive sputtering approach. Compositionally graded Fe_xW_1-xN and Fe_xMo_1-xN amorphous films were deposited at room temperature and subsequently annealed in NH₃ to induce crystallization of the ordered layered phase. Interestingly, structural characterization by synchrotron GIWAXS reveals the formation of the layered phase within wide compositional ranges, suggesting the layered structure can accommodate cation off-stoichiometry. XAS characterization around the Fe K-edge highlights an interesting evolution of the chemical state with composition. Initial electrical and magneto transport measurements show distinct behavior correlated with composition and phase evolution. This combinatorial synthesis platform enables rapid exploration of synthesis windows and structure–property relationships in layered ternary nitrides as candidates for quantum materials applications.