Fig. 1
Pure spin current. a Illustration of pure spin current. Spin-up and spin-down electrons move in the opposite directions, resulting in the flow of pure spin current without companying any charge current. b Pure spin current in the spin transistors or logic devices. Two ferromagnetic or heavy metallic electrodes are used for pure spin current injection/detection. The pure spin current could be injected via electrical charge current spin injection, spin pumping, spin Seebeck effect, and spin Hall effect, etc. Pure spin current flows in the spin channel that carries information. c Illustration of the diffusion of pure spin current in spin channels with the presence of spin scattering. µs is the spin-dependent chemical potential. d Schematic of spin–orbit torque at the interface between a non-magnetic metal (NM) with large spin orbit coupling and a ferromagnet (FM). e Illustration of the spin–transfer torque from spin current on FM
