# Giant anisotropy of Gilbert damping in epitaxial CoFe films

## TL;DR

This paper reports a significant anisotropy in Gilbert damping in epitaxial CoFe thin films, driven by orientation-dependent spin-orbit coupling, with potential implications for spintronics device optimization.

## Contribution

It demonstrates a giant Gilbert damping anisotropy in epitaxial CoFe films and links it to variations in spin-orbit coupling across different magnetization orientations.

## Key findings

- Maximum-minimum damping ratio of 400%
- Damping anisotropy correlates with anisotropic magnetoresistance
- Spin-orbit coupling variation explains damping anisotropy

## Abstract

Tailoring Gilbert damping of metallic ferromagnetic thin films is one of the central interests in spintronics applications. Here we report a giant Gilbert damping anisotropy in epitaxial Co$_{50}$Fe$_{50}$ thin film with a maximum-minimum damping ratio of 400 \%, determined by broadband spin-torque as well as inductive ferromagnetic resonance. We conclude that the origin of this damping anisotropy is the variation of the spin orbit coupling for different magnetization orientations in the cubic lattice, which is further corroborate from the magnitude of the anisotropic magnetoresistance in Co$_{50}$Fe$_{50}$.