Phase composition, structure, and magnetic properties of Fe–Zr–N films produced by magnetron sputtering of heated target

Abstract

The phase-structural state and magnetic properties, specifically, the saturation induction B_s and the coercive field H_c, of Fe–Zr–N films are characterized in a wide range of chemical compositions. The films are obtained by reactive magnetron sputtering in an Ar + N₂ atmosphere at different concentrations of N₂ (0, 5, and 15 vol %) using the FeZr_X targets heated above the Curie temperature. Single-phase (bcc α-Fe(Zr,N) solid solution), two-phase (α-Fe(Zr,N) + Fe₄N, α-Fe + ZrO_2–x), and three-phase (α-Fe(Zr,N) + Fe₄N + Fe₃N) films with a nanocrystalline (grain size of 2 to 14 nm), amorphous, and mixed (amorphous + nanocrystalline) structure are formed. The nanocrystalline films are strong ferromagnets exhibiting a high saturation induction B_s (0.5 to 2.1 T) and low coercive field H_c (40 to 1100 A/m). The films with the amorphous and mixed (amorphous + nanocrystalline) structure are weak ferromagnets (B_s is about 1 to 7 mT).