Fig. 1: SAM transfer in HM/FM/Insulator and AFI/FM metal/Insulator.
From: Magnetization switching driven by magnonic spin dissipation
a Schematic illustration of the spin transfer mechanism in conventional HM/FM/Insulator. When a charge current (\({{{I}}}_{{{C}}}\)) is applied along the x-axis in the HM layer, SHE generated a spin current carrying SAM (\({J}_{\tt{in}}\)) into the adjacent FM layer. The net SAM (\({J}_{{S}}^{\tt{net}}\)) in the FM layer is then equivalent to the incoming \({J}_{\tt{in}}\), resulting in a specific amount of spin torques exerted on the magnetization (M) due to the transverse spin component. b Schematic illustration of spin transfer through magnonic spin dissipation in AFI/FM/Insulator. The charge current \({I}_{C}\) flowing in a ferromagnetic metal generates ISC via the SHE within the FM layer. The SAM flowing toward the normal insulator is entirely reflected at their interface (\({J}_{\tt{out}}\)). Conversely, the SAM with the opposite sign moving toward the AFI is partially transferred to the AFI layer, being converted into magnons, with the remaining SAM reflected back to the FM at the FM/AFI interface (\({J}_{\tt{ref}{{1}}}\)). The magnons reflected at the outer boundary of the AFI layer carry the SAM back to the FM (\({J}_{\tt{{ref}}{{2}}}\)). The net SAM \({J}_{{{S}}}^{\tt{{net}}}\) in the FM layer then is given by the total sum of three incoming SAM, \(-{J}_{\tt{{out}}}+{J}_{\tt{{ref}}{{1}}}+{J}_{\tt{{ref}}{{2}}}\). In the absence of magnon dissipation, \(-{J}_{\tt{{out}}}+{J}_{\tt{{ref}}{{1}}}+{J}_{\tt{{ref}}{{2}}}\) becomes zero. However, in the presence of non-zero magnon dissipation, it results in the non-zero spin transfer to M.
