Magnetic Damping in Epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mi>Iron</mml:mi></mml:math> Alloyed with Vanadium and Aluminum
David A. Smith, Anish Rai, Youngmin Lim, Timothy Q. Hartnett, Arjun Sapkota, Abhishek Srivastava, Claudia Mewes, Zijian Jiang, Michael Clavel, Mantu K. Hudait, Dwight D. Viehland, Jean J. Heremans, Prasanna V. Balachandran, Tim Mewes, Satoru Emori
Abstract
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 $\mathrm{Al}$. $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{V}$ alloys exhibit lower intrinsic damping compared with that of pure $\mathrm{Fe}$, reduced by nearly a factor of 2, whereas damping in $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Al}$ 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, $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{V}$ is confirmed to exhibit an intrinsic Gilbert damping parameter of about 0.001, which is among the lowest ever reported for ferromagnetic metals.