Determination of spin pumping as a source of linewidth sputtered Co90Fe10/Pd multilayers by use of broadband ferromagnetic resonance spectroscopy

Published

February 10, 2012

Author(s)

Justin M. Shaw, Hans T. Nembach, Thomas J. Silva

Abstract

We performed a systematic study of damping in Co₉₀Fe₁₀/Pd multilayers by use of broadband (1– 60 GHz) ferromagnetic resonance (FMR) spectroscopy in the perpendicular geometry. The data were fitted with the conventional Landau-Lifshitz equation in conjunction with an inhomogeneous contribution to linewidth {Δ}H₀. Samples were prepared with net perpendicular anisotrpy field values ranging from -0.5 to +1.2 T. {Δ}H₀ shows a dependence on the perpendicular anisotropy, through the Landau-Lifshitz damping parameter α, which ranged from 0.016 to 0.04, exhibits no trend as a function of anisotropy. We explain the wide variation of α as a result of spin-pumping from Co₉₀Fe₁₀ into adjacent nonmagnetic layers. We use a quantitative model for spin pumping that includes the intrinsic spin-mixing conductance at the Co₉₀Fe₁₀/Pd interface and the spin-diffusion length of Pd, which were experimentally measured at room temperature to be (1.07 {plus or minus} 10¹⁹ m^-2 and 8.6 {plus or minus} 1.0 nm, respectively. We quantitatively show how α is enhanced by spin pumping through an FMR investigation of individual Pd/CoFe/Pd, and Pd/CoFe/Pd/CoFe/Pd layer structures.

Citation

Physical Review B

Pub Type

Journals

Keywords

Ferromagnetic resonance, perpendicular anisotropy, spin-pumping, damping

Citation

Shaw, J. , Nembach, H. and Silva, T. (2012), Determination of spin pumping as a source of linewidth sputtered Co₉₀Fe₁₀/Pd multilayers by use of broadband ferromagnetic resonance spectroscopy, Physical Review B (Accessed October 8, 2025)