To develop low-moment, low-damping metallic ferromagnets for power-efficient spintronic devices, it is crucial to understand how magnetic relaxation is impacted by the addition of nonmagnetic elements. Here, we compare magnetic relaxation in epitaxial $\mathrm{Fe}$ films alloyed with light, nonmagnetic elements of $\mathrm{V}$ and $\mathrm{Al}$. $\mathrm{Fe}\text{−}\mathrm{V}$ alloys exhibit lower intrinsic damping compared with that of pure $\mathrm{Fe}$, reduced by nearly a factor of 2, whereas damping in $\mathrm{Fe}\text{−}\mathrm{Al}$ alloys increases with $\mathrm{Al}$ content. Our experimental and computational results indicate that reducing the density of states at the Fermi level, rather than the average atomic number, has a more significant impact on lowering damping in $\mathrm{Fe}$ alloyed with light elements. Moreover, $\mathrm{Fe}\text{−}\mathrm{V}$ is confirmed to exhibit an intrinsic Gilbert damping parameter of about 0.001, which is among the lowest ever reported for ferromagnetic metals.

• Received 26 May 2020
• Revised 21 July 2020
• Accepted 10 August 2020

DOI:https://doi.org/10.1103/PhysRevApplied.14.034042