Abstract
We present a detailed study of the photoinduced magnetization precession and magnetic relaxation in epitaxial Pd/Fe films on MgO(001) substrates via all-optical pump-probe techniques. We explicitly formulate the correlation between the Gilbert damping and the effective damping in the optical approach. Furthermore, a non-local Gilbert damping induced by spin pumping is demonstrated self-consistently by the Gilbert damping dependence on Pd thickness and the 1/d_Fe relationship of damping with Fe thickness d_Fe. The non-local Gilbert damping enables the determination of spin diffusion length λ_SD=(7.4±3.0) nm in Pd and interfacial spin mixing conductance g^(↑↓)=(2.7±0.4)×〖10〗^19 〖nm〗^(-2). Our work paves a way towards the optical determination of spin transport parameters.