We have discovered a giant anisotropy of Gilbert damping, by 400%, in metallic epitaxial Co50Fe50 thin film devices. This large anisotropy is found to originate from the variation of spin-orbit coupling in the disordered cubic alloy.
Significance and Impact
This discovery and the underlying mechanism open a novel strategy to tune the intrinsic Gilbert damping in metallic ferromagnets, a key parameter that is crucial for applications such as magnetoresistive random-access memories (MRAM) and magnonics.
- Up to 400% change of Gilbert damping is obtained in epitaxial Co50Fe50 thin-film devices, measured by both spin-torque and inductive ferromagnetic resonance.
- First-principles calculations point to the variation of spin-orbit coupling in disordered cubic alloy as the origin of the damping anisotropy in Co50Fe50, which is further corroborated by the angular dependence of anisotropic magnetoresistance.
Work was performed in part at Argonne’s Computation facility.
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