Temperature-Dependent Spin Dynamics in WSe₂/Pt/CoFe Trilayers

In this work, magnetic anisotropy, magnetic damping factor ( α _ s ), and effective spin-mixing conductance ( g^\uparrow \downarrow _ eff ) were studied at different temperatures ( T ) for WSe2/Pt/CoFe heterostructure with various WSe2 monolayer numbers ( n_ ML ). We observed that the insertion of the WSe2 underlayer could weaken the perpendicular uniaxial magnetic anisotropy due to increased interfacial roughness and decreased orbital hybridization. A similar enhancement of α _ s is obtained for n_ ML = 1-5 at room temperature (RT), which mainly arises from the contributions of interfacial two-magnon scattering (TMS) and extra spin current absorption by the WSe2 layer. As T drops below 150 K, both α _ s and g^\uparrow \downarrow _ eff decrease significantly, gradually close to the value of the Pt/CoFe bilayer. In addition, it is found that the sample of n_ ML = 1 exhibits larger magnetic coercivity and shorter relaxation time than other samples, which can be attributed to the poor quality of 1 ML WSe2 and the increased magnetic inhomogeneities at the Pt/CoFe interface. Our work elucidates the significant implications of 2D materials on the magnetic properties, which will be valuable for the development of transition-metal dichalcogenide (TMD)-based spintronic devices.