Abstract: γ′-Fe₄N thin films were deposited on single crystal Si (100) substrate by DC magnetron sputtering using an Ar/N₂ gas mixture (N₂/(Ar+N₂)=10％). The structure and magnetic properties of the films were characterized via Xray diffraction (XRD) and superconducting quantum interference device (SQUID). The effect of substrate bias voltage on magnetic properties of γ′-Fe₄N thin films were investigated. With the increase of substrate bias voltage, the efficiency of the reaction between Fe and N and the growth rate for γ′-Fe₄N were improved, the films obtained were smooth, and the values of M_s for all the FeN films were almost the same, but their coercivity was decreased.

Key words: γ′-Fe₄N thin film, substrate bias voltage, magnetic property