First-principles spin transport and relaxation in magnetic heterostructures

In this talk, I review a first-principles scattering formulation of quantum transport that has been used to study resistivity, spin-flip diffusion, Gilbert damping and spin Hall effects in a wide range of magnetic heterostructures that form the active parts of spintronics devices. By simultaneously including spin-orbit coupling (SOC), noncollinear magnetization and temperature-induced disorder, I demonstrate how we are able to identify novel properties arising from the interplay of these effects. As an example, I show the enhancement of Gilbert damping observed in thin Ni80Fe20 films in contact with the nonmagnetic metals that is quantitatively reproduced allowing us to generalize the "spin-pumping" theory to take SOC into account explicitly. One conclusion that can be drawn from this is that the interface spin-memory loss needs to be included in analyzing spin-pumping experiments. The keen debate on the spin-flip diffusion length of platinum is well reconciled under the light shed by our first-principles calculations. Finally, I show that the Gilbert damping can be significantly enhanced by noncollinearity; how it is modified depends on the particular precession modes. The influence of this texture-enhanced damping on the domain wall dynamics is illustrated using a generalized Thiele equation.