Local charge and spin currents are evaluated from the solutions of fully relativistic quantum mechanical scattering calculations for systems that include temperature-induced lattice and spin disorder as well as intrinsic alloy disorder. This makes it possible to determine material-specific spin transport parameters at finite temperatures. Illustrations are given for a number of important materials and parameters at 300 K. The spin-flip diffusion length l sf of Pt is determined from the exponential decay of a spin current injected into a long length of thermally disordered Pt; we find l Pt sf = 5.3 ± 0.4 nm. For the ferromagnetic substitutional disordered alloy Permalloy (Py), we inject currents that are fully polarized parallel and antiparallel to the magnetization and calculate l sf from the exponential decay of their difference; we find l Py sf = 2.8 ± 0.1 nm. The transport polarization β is found from the asymptotic polarization of a charge current in a long length of Py to be β = 0.75 ± 0.01. The spin Hall angle ΘsH is determined from the transverse spin current induced by the passage of a longitudinal charge current in thermally disordered Pt; our best estimate is Θ Pt sH = 4.5±1% corresponding to the experimental room temperature bulk resistivity ρ = 10.8µΩ cm.arXiv:1901.00703v1 [cond-mat.mes-hall]

The discontinuity of a spin-current through an interface caused by spin-orbit coupling is characterized by the spin memory loss (SML) parameter δ. We use first-principles scattering theory and a recently developed local current scheme to study the SML for Au|Pt, Au|Pd, Py|Pt and Co|Pt interfaces. We find a minimal temperature dependence for nonmagnetic interfaces and a strong dependence for interfaces involving ferromagnets that we attribute to the spin disorder. The SML is larger for Co|Pt than for Py|Pt because the interface is more abrupt. Lattice mismatch and interface alloying strongly enhance the SML that is larger for a Au|Pt than for a Au|Pd interface. The effect of the proximity induced magnetization of Pt is negligible. arXiv:2001.11520v1 [cond-mat.mes-hall] 30 Jan 2020

Little is known about the spin-flip diffusion length l sf , one of the most important material parameters in the field of spintronics. We use a density-functional-theory based scattering approach to determine values of l sf that result from electron-phonon scattering as a function of temperature for all 5d transition metal elements. l sf does not decrease monotonically with the atomic number Z but is found to be inversely proportional to the density of states at the Fermi level. By using the same local current methodology to calculate the spin Hall angle Θ sH that characterizes the efficiency of the spin Hall effect, we show that the products ρðTÞl sf ðTÞ and Θ sH ðTÞl sf ðTÞ are constant.

Symmetry lowering at an interface leads to an enhancement of the effect of spin-orbit coupling and to a discontinuity of spin currents passing through the interface. This discontinuity is characterized by a "spin-memory loss" (SML) parameter δ that has only been determined directly at low temperatures. Although δ is believed to be significant in experiments involving interfaces between ferromagnetic and nonmagnetic metals, especially heavy metals like Pt, it is more often than not neglected to avoid introducing too many unknown interface parameters in addition to often poorly known bulk parameters like the spin-flip diffusion length l sf . In this work, we calculate δ along with the interface resistance AR I and the spin-asymmetry parameter γ as a function of temperature for Co|Pt and Py|Pt interfaces where Py is the ferromagnetic Ni 80 Fe 20 alloy, permalloy. We use first-principles scattering theory to calculate the conductance as well as local charge and spin currents, modeling temperature-induced disorder with frozen thermal lattice and, for ferromagnetic materials, spin disorder within the adiabatic approximation. The bulk and interface parameters are extracted from the spin currents using a Valet-Fert model generalized to include SML.

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