Enhanced Spin Pumping and Magnetization dynamics in Ni$_{80}$Fe$_{20}$/MoS$_2$ stack via interface modification

Abstract

Materials with strong spin orbit coupling (SOC) are essential for realizing spin orbit torque (SOT) based magnetic memory devices. Transition metal dichalcogenides (TMDs) are promising candidates for such appli cations because of their inherently high SOC strength. In this study, we investigate the spin pumping effect at the interface between a monolayer of molybdenum disulfide (ML-MoS$_2$) and Ni$_{80}$Fe$_{20}$ (Py) thin films using broadband ferromagnetic resonance (FMR) spectroscopy. FMR measurements reveal a notable enhancement in the effective Gilbert damping factor for the ML-MoS$_2$/Py (Pt = 0 nm) interface compared to the reference Py thin films, attributed to spin pumping across the ML-MoS$_2$/Py interface. To further quantify spin pumping efficiency, we introduce a high SOC platinum (Pt) interlayer at the ML-MoS$_2$/Py interface and systematically vary its thickness. This allows us to evaluate key spin transport parameters, including the enhancement in the effective Gilbert damping parameter, the effective spin mixing conductance that reflects the transfer of spin angular momentum from Py to ML-MoS$_2$ and the effective spin current density.