High-frequency behavior of FeN thin films fabricated by reactive sputtering

TL;DR

This study explores the high-frequency magnetic resonance behavior of FeN thin films fabricated by reactive sputtering, revealing how nitrogen flow rate influences magnetic properties and damping mechanisms.

Contribution

It provides detailed analysis of the relationship between nitrogen flow rate, static magnetic properties, and high-frequency magnetic resonance in FeN thin films.

Findings

FMR observed between 2-18 GHz in FeN films.

FMR frequency decreases with increasing nitrogen flow rate.

Low-field damping sensitive to nitrogen flow rate, indicating extrinsic effects.

Abstract

We investigated high-frequency behavior of FeN thin films prepared by reactive sputtering through ferromagnetic resonance (FMR) and its relationship with the static magnetic properties. The FMR was observed in the frequency range from 2 to 18 GHz in the FeN films fabricated at proper nitrogen flow rate (NFR). In those FeN thin films, a decrease of the saturation magnetization and the corresponding decrease of the FMR frequency were observed as NFR was increased during the deposition. The external field dependences of the FMR frequencies were well fit to the Kittel formula and the Land\'e g-factors determined from the fit were found to be very close to the free electron value. The high-field damping parameters were almost insensitive to the growth condition of NFR. However, the low-field damping parameters exhibited high sensitivity to NFR very similar to the dependence of the hard-axis coercivity on NFR, suggesting that extrinsic material properties such as impurities and defect structures could be important in deciding the low-field damping behavior.