Anisotropic intrinsic damping constant of epitaxial Co₂MnSi heusler alloy films

We investigated the Gilbert damping constant of the Heusler Co ₂MnSi(001) films epitaxially grown on a MgO(100) substrate by a ferromagnetic resonance technique. The angular variation in resonance field in the in-plane geometry exhibited a maximum when the field was applied parallel to the [110] direction (easy axis), and its relative minimum corresponded to the H ∥ [100] hard axis. Experimental results were fitted with theoretical results; the g-value, effective magnetization and anisotropy constants were determined. The magneto-crystalline anisotropy of the films decreased after the films were postannealed at 400°C. The Gilbert damping parameter was anisotropic and had a minimum value at 300°C.