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

In this work, magnetic anisotropy, magnetic damping factor (
$\alpha _{\text {s}}$
), and effective spin-mixing conductance (
$g^{\uparrow \downarrow }_{\text {eff}}$
) were studied at different temperatures (
$T$
) for WSe2/Pt/CoFe heterostructure with various WSe2 monolayer numbers (
$n_{\mathrm {ML}}$
). 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
$\alpha _{\text {s}}$
is obtained for
$n_{\mathrm {ML}}$
= 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
$\alpha _{\text {s}}$
and
$g^{\uparrow \downarrow }_{\text {eff}}$
decrease significantly, gradually close to the value of the Pt/CoFe bilayer. In addition, it is found that the sample of
$n_{\mathrm {ML}}$
= 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.