FeZrN Films with Nanocomposite Structure for Soft Magnetic Applications

Abstract

The Fe_56.8–72.5Zr_5.9–11.6N_13.8–31.6O_1.2–3.4 films were prepared by magnetron deposition. The metastable structural and phase state, which was formed upon deposition, is represented by either mixed (nanocrystalline αFe(Zr,N) + amorphous) or amorphous structure. During subsequent annealing (300–600°C), it slightly shifts toward the stable state due to partial crystallization of the amorphous phase and precipitation of the secondary phases (Fe₄N, Fe₃N, and ZrO₂). The grain structure of the films (grains 3–12 nm in size) is characterized by thermal stability. The relatively low saturation magnetization M_s (870–1400 G) of the films is explained by the presence of the amorphous phase and αFe(Zr,N) solid solution, which remain in the film structure after annealing at all temperatures. The stochastic domain structure is formed in all films under study due to exchange interaction between grains and clusters in the amorphous structure. The strong dependence of the magnetic structure on the phase state and grain structure of the films is demonstrated. The combination of low local magnetic anisotropy and the highest stochastic domain size predetermines the lowest coercive field of the films, which varies in a range of 1 to 50 Oe.