6533b855fe1ef96bd12b132d

RESEARCH PRODUCT

Gilbert damping of CoFe-alloys

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description

We report structural, magnetic and dynamic properties of polycrystalline Coalt;subagt;xalt;/subagt;Fealt;subagt;1-xalt;/subagt;-alloy films on Sapphire, Silicon and MgO substrates across the full composition range, by using a Vector Network Analyser ferromagnetic resonance measurement technique (VNA-FMR), Superconducting Quantum Interference Device magnetometry (SQUID) and X-Ray Diffraction (XRD). In the approximate vicinity of 28% Co, we observe a minimum of the damping parameter, associated with a reduction in the density of states to a minimum value at the Fermi energy level. For films on all substrates, we find magnetic damping of the order of 4-5⋅10alt;supagt;-3alt;/supagt;, showing that the substrate does not play a major role. Using a post-annealing process, we report a decrease of the magnetic damping down to 3-4⋅10alt;supagt;-3alt;/supagt;. We find that the saturation magnetization depends approximately reciprocally on the damping parameter with varying alloy composition.