Thickness Dependence Ferromagnetic Resonance in Ta/Ni81Fe19 Bilayer Nanostructures

Broadband in-plane ferromagnetic resonance was performed in Ta/Ni81Fe19 (Py) bilayer nanostructure in which the thickness of both Ta and Py layers has been varied in the range comparable to spin diffusion length lambda(SD) of normal metal. The ratio of symmetric Lorentzian to anti-symmetric Lorentzian peaks decreases from 12.22 to 1.28. We have shown that both Spin Hall Effect and spin pumping increase and total Gilbert damping constant alpha increases with decrease in thickness of bilayer.