Extending the Growth Temperature-N Concentration Regime Through Pd Doping in Fe4N Thin Films

TL;DR

This paper demonstrates that Pd doping in Fe4N thin films extends the growth temperature-N concentration regime, enabling better phase control while maintaining key magnetic properties, which is promising for spintronic applications.

Contribution

It introduces Pd doping as a method to expand the Fe4N phase formation regime without compromising its properties.

Findings

Pd atoms substitute corner Fe atoms in Fe4N.

Saturation magnetization decreases slightly with Pd doping up to 13 at%.

Pd doping effectively extends the Fe4N growth regime.

Abstract

Fe4N is a well-known anti-perovskite compound exhibiting high magnetization, high chemical stability, low coercivity, high Curie temperature, and high spin-polarization ratio. Therefore, it is a viable candidate for applications in spintronic and magnetic storage devices. However, the Fe4N phase is formed in a narrow substrate temperature (Ts)-N concentration (Nc) regime in the phase diagram of Fe-N. It has been observed that a slight N deficiency will lead to impurity of alpha-Fe, and some N efficiency would result in epsilon-Fe3N phase. Through this work, it has been demonstrated that the doping of Pd can be suitably utilized to extend the Ts-Nc regime for the growth of Fe4N thin films. EXAFS analysis indicate that Pd atoms are substituting corner Fe atoms. Magnetization measurements reveal that the saturation magnetization reduces nominally with Pd doping up to 13 at.%. Therefore, it is foreseen that Pd doping is effective in extending the Fe4N phase formation regime without a significant impact on its structural, electronic, and magnetic properties.