Anisotropic gilbert damping in B2 ordered full Heusler alloy Co2MnAl thin films

Abstract

Structural and dynamic magnetization properties of Co2MnAl (CMA) full Heusler alloy thin films grown on Si (100) substrate at different substrate temperatures (Ts) 30°C, 200°C, 300°C, 400°C and 500°C are investigated. XRD patterns revealed the formation of B2 partially ordered phase at Ts=200°C and above. Ferromagnetic Resonance (FMR) technique have been used to determine the damping constant (α), resonance field (Hr) and line width (ΔH) of recorded spectra and fitted by using Landau-Lifshitz-Gilbert (LLG) equation. The lowest damping constant was found to be 0.007±0.002 for the film grown at Ts=200°C. Films exhibit uniaxial magnetic anisotropy. Anisotropic damping constant α is calculated along the easy and hard axis. Along the two directions remarkable change (almost ∼59%) in α is observed.