The structure and magnetic properties of FeNiN films

Abstract

FeNiN films with 0–56 at % Ni concentrations were prepared by dual ion beam sputtering in a nitrogen–argon gas mixture. Effects of nitrogen and nickel concentrations on the structure and magnetic properties of FeNiN films have been studied. FeNiN films with lower nickel and nitrogen concentrations contained the bcc α-(FeNi) phase, films with 8–12 at % nitrogen and 5–25 at % Ni concentrations contained α″-(Fe, Ni)16N2 and γ′-(Fe, Ni)4N phases, and films with 30–56 at % Ni concentrations consisted of a mixture of fcc γ-FeNi alloy and γ′-(Fe, Ni)4N phases. The FeNiN films with 8–12 at % nitrogen and 5–15 at % nickel concentrations showed high saturation magnetization of 2.2–2.3 T and low coercivity of 96–110 A/m. The variation of the magnetic properties was attributed to the change in the structure of the films.