Synthesis and properties of Fe3C film by r.f. magnetron sputtering

Fe₃C film, which is a promising new magnetic recording material, can be synthesized by r.f. magnetron sputtering. Several graphite plates were attached to an iron plate to adjust the area of a composite target for the control of film composition. The crystalline phases in a film changed from Fe-C solid solution to Fe₃C with increasing substrate temperature from 350 °C and above. Sputtering at an argon pressure of 5 Pa was favourable for the formation of crystalline Fe₃C film. All Fe₃C films showed in-plane magnetization. The saturation magnetization of the film was around 100–120 e.m.u. g^–1 regardless of the deposition conditions. The coercivity of the films increased from 1 Oe to 250 Oe with increasing substrate temperature, and the coercivity remained constant at 250 Oe at 350 °C, regardless of argon pressure.