Magnetic and structural properties of iron nitride thin films obtained by argon-nitrogen reactive radio-frequency sputtering

We have prepared iron nitride thin films by reactive rf sputtering of an iron target in an argon-nitrogen plasma. The films present a wide variety of structures and compositions: α expanded bcc iron, amorphous Fe1−x-Nx, γ′-Fe4N, ε-Fe2–3N, and ζ-Fe2N. Evolutions of the crystallographic structures and of the magnetic properties of the obtained phases are discussed versus the nitrogen concentration in the gaseous flow and the substrate temperature during deposition.