Structural and magnetic properties of rf‐sputtered iron nitrides using NH3 (abstract)

Thin films of iron nitrides have attracted much attention due to their superior magnetic properties. Conventional rf reactive sputtering using N2 gas encounters a number of difficulties, including mixed phases, which are alleviated by the use of NH3 gas. By controlling the partial pressure of NH3, we have been able to fabricate all stable Fe nitrides of ζ‐Fe2N, e‐Fe2–3N, and γ’‐Fe4N in single‐phase films. The structure has been determined using an x‐ray diffractometer. The magnetic properties have been investigated using VSM, SQUID magnetometers, and Mossbauer spectroscopy. All nitrides except Fe2N have high saturation moments with a large in‐plane anisotropy. The saturation moment decreases with increasing nitrogen concentration. The Mossbauer results, in excellent agreement with those from bulk samples, are consistent with structural results and magnetization measurements.