Investigation of γ′-Fe4N thin films deposited on Si(1 0 0) and GaAs(1 0 0) substrates by facing target magnetron sputtering

• The film on GaAs shows preferred orientation along (1 0 0).
• The film on Si exhibits a higher Ms and lower Hc.
• It turned out that Hc is chiefly affected by the intrinsic stress.
• Ms increase with decrease in lattice mismatch.

γ′-Fe4N thin films with good soft magnetic properties were successfully prepared on single crystal Si(1 0 0) and GaAs(1 0 0) substrates with Fe buffer layer by facing target magnetron sputtering. The microstructure and magnetic properties of the samples at low temperature were investigated. Both structural and magnetic properties of the films were shown to be influenced by the substrate. Specifically, the film deposited on the GaAs exhibited a strong preferred orientation along the (1 0 0) plane, while the film deposited on Si exhibited higher saturation magnetization (Ms) and lower coercivity (Hc). The results suggest that the coercivity is probably related to the intrinsic stress and that Ms increases whereas Hc decreases with decreasing lattice mismatch. The Mr/Ms ratio decreased with decreasing temperature due to the effect of the thermal disturbance on the magnetization. Both films had a single easy magnetized direction parallel to the substrate plane.