Colossal Gilbert Damping Anisotropy in Heusler‐Alloy Thin Films

Abstract

Abstract Manipulating Gilbert damping is of critical importance in spintronic devices. Here, this work reports the damping anisotropy of Heusler‐alloy Co3−xFexAl single crystalline thin films using inductive ferromagnetic resonance. A colossal Gilbert damping anisotropy ratio of up to 1400%, nearly three times higher than the highest value reported among known metallic ferromagnets, is observed in the optimized sample Co1.4Fe1.6Al. The Gilbert damping anisotropy with strong fourfold symmetry is attributed to the variation of the spin–orbit coupling, which is further corroborated by the current‐orientation‐dependent anisotropic magnetoresistance ratio in Co1.4Fe1.6Al thin film. These results provide a practical approach to adjust Gilbert damping continuously and show great promise for future spintronic applications.

Keywords

• anisotropic magnetoresistance
• Gilbert damping anisotropy
• half‐metallicity
• Heusler alloy
• spin–orbit coupling