Ferromagnetic resonance spectra in patterned and unpatterned NiFe/Pt films

The ferromagnetic resonance in nanostructured Ni₈₁Fe ₁₉ films comprising Aim parts and wire parts covered with Pt has been investigated. In contrast to the systematic variation of the FMR linewidth for the film parts, the linewidth for the nanostructured wire parts shows an irregular change with changing the thickness of Pt. This irregular change indicates that the spin current absorption in the Pt layer cannot fully account for the linewidth change in the wire parts. This FMR-linewidth variation can be argued in terms of the competition between the spin pumping and the roughness effect.