Ferromagnetic resonance (FMR) was measured for Cu/permalloy (Py) (20, 30, 40 Å)/Cu (dCu)/Pt (0, 50 Å) films with various dCu to clarify the effect of spin diffusion driven by the precession of magnetization on Gilbert damping. The peak-to-peak linewidth ΔHpp of the FMR spectra for Cu/Py/Cu/Pt films was very large at dCu = 0 Å, and decreased remarkably at dCu = 30 Å. Above dCu = 30 Å, it decreased gradually with increasing dCu in the anomalously wide range of dCu. The out-of-plane angular dependence of the FMR of Cu/Py(30 Å)/Cu (dCu)/Pt (0, 50 Å) films was measured and analyzed using a Landau-Lifshitz-Gilbert equation that took into account the local variation of the effective demagnetizing field. The Gilbert damping coefficient G obtained from the analysis for Cu/Py/Cu/Pt films was about twice as large as that for Cu/Py/Cu films even at dCu = 100 Å and decreased gradually as dCu increased. At dCu = 2000-3000 Å, G for Cu/Py/Cu/Pt and Cu/ Py/Cu films has the same value. We discussed the influence of spin diffusion driven by the precession of magnetization in FMR on G using a previously proposed model. The calculated G vs dCu fitted well to the experimental one, and the other features of the experimental results are well explained by the model.
|Number of pages||9|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2002 Sep 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics