Effect of dopants on thermal stability and self-diffusion in iron nitride thin films

TL;DR

This study investigates how different dopants (Al, Ti, Zr) influence the thermal stability and self-diffusion in iron nitride thin films, revealing dopant-specific effects on diffusion and stability.

Contribution

It provides detailed insights into how specific dopants affect self-diffusion and thermal stability in iron nitride thin films, highlighting the dominant role of Fe diffusion.

Findings

Al doping suppresses N self-diffusion

Ti and Zr doping accelerate N diffusion

Fe self-diffusion is suppressed by dopants with lower nitride formation heat

Abstract

We studied the effect of dopants (Al, Ti, Zr) on the thermal stability of iron nitride thin films prepared using a dc magnetron sputtering technique. Structure and magnetic characterization of deposited samples reveal that the thermal stability together with soft magnetic properties of iron nitride thin films get significantly improved with doping. To understand the observed results, detailed Fe and N self-diffusion measurements were performed. It was observed that N self-diffusion gets suppressed with Al doping whereas Ti or Zr doping results in somewhat faster N diffusion. On the other hand Fe self-diffusion seems to get suppressed with any dopant of which heat of nitride formation is significantly smaller than that of iron nitride. Importantly, it was observed that N self-diffusion plays only a trivial role, as compared to Fe self-diffusion, in affecting the thermal stability of iron nitride thin films. Based on the obtained results effect of dopants on self-diffusion process is discussed.