Relaxation Dynamics of Sputtered Fe80Co20 Thin Films on Different Substrates: Micromagnetic Validation

Abstract

In the present investigation, we have demonstrated the effect of different substrates (Si, SiO ₂ ${\rm{, }}\;\text{and}\;\text {{A}}{{{\text {l}}}_{2}}{{{\text {O}}}_{3}}$ ) and deposition temperatures ( T_D = 27 °C to 450 °C) of sputtered Fe ₈₀ Co ₂₀ ferromagnetic thin films of 30 nm thickness on their microstructural, static, and dynamic properties. The lowest value of Gilbert damping (α _eff ) of 5.1 $ \times\, 10$ ⁻³ with a high saturation magnetization ( M_S ) is the outcome of the improved atomic ordering and overall film crystallinity with ultralow interfacial roughness (0.23 ± 0.03 nm) of 400 °C grown films. The structural analysis from atomic force microscopy depicts temperature-dependent improvement in films grown at 400 °C. From ferromagnetic resonance and vibrating sample magnetometry experiments, magnetization was determined to be the highest M_S $ \approx \text {1628.8}\ {\rm{emu/cc}}$ for the films grown at 400 °C. We have validated the above-mentioned experimental data through micromagnetic simulation using ubermag and an object-oriented micromagnetic framework that is used in backend for computation.