Spin Drift-Diffusion Boundary Conditions for FEM Modeling of Multilayer SOT Devices

We present results obtained from solving the drift-diffusion equations for spin transport with the finite element method in a ferromagnet/heavy metal/ferromagnet (FM/HM/FM) trilayer, using boundary conditions which account for partial absorption of spins at the HM/FM interfaces. We demonstrate the flexibility of the approach by treating different levels of absorption, and by showing that in the limit of full absorption, the results obtained with the boundary conditions agree with the ones obtained from magnetoelectronic circuit theory.