Magnetization reversal, damping properties and magnetic anisotropy of L10-ordered FeNi thin films

TL;DR

This study investigates the magnetic reversal mechanisms, damping properties, and anisotropy in L10-ordered FeNi thin films, revealing domain wall motion-driven reversal and optimal damping at moderate anisotropy levels.

Contribution

It demonstrates the fabrication of L10-FeNi films with tunable anisotropy and provides detailed analysis of their magnetic reversal and damping characteristics.

Findings

Magnetization reversal occurs via domain wall motion.

Moderate anisotropy yields low damping constant (~4.9×10^-3).

Films exhibit a mix of cubic and uniaxial anisotropies.

Abstract

L10 ordered magnetic alloys such as FePt, FePd, CoPt and FeNi are well known for their large magnetocrystalline anisotropy. Among these, L10-FeNi alloy is economically viable material for magnetic recording media because it does not contain rare earth and noble elements. In this work, L10-FeNi films with three different strengths of anisotropy were fabricated by varying the deposition process in molecular beam epitaxy system. We have investigated the magnetization reversal along with domain imaging via magneto optic Kerr effect based microscope. It is found that in all three samples, the magnetization reversal is happening via domain wall motion. Further ferromagnetic resonance (FMR) spectroscopy was performed to evaluate the damping constant and magnetic anisotropy. It was observed that the FeNi sample with moderate strength of anisotropy exhibits low value of damping constant ~ 4.9X10^-3. In addition to this, it was found that the films possess a mixture of cubic and uniaxial anisotropies.