GENERALIZED MAGNETOELECTRONIC CIRCUIT THEORY AND SPIN RELAXATION AT INTERFACES IN MAGNETIC MULTILAYERS

Abstract

Spintronic devices that rely on spin transport at metal surfaces are thought to operate using spin pumping, spin-transfer torque, and extremely high magnetoresistance. In some of these devices, the relationship between spin and orbit is critical. To be more exact, spin-orbit coupling absorbs a small portion of the inbound spin current at the contact. By elaborating on the concept of spin-mixing conductance, we develop a full theory of magnetoelectronic circuits that describes the various ways that spin-flip scattering occurs. We present a simple equation that characterizes spin-mixing conductance in terms of the contributions that induce spin precession, spin torque, and spin relaxation, also known as spin memory loss. This is for the most prevalent type of exchange contact. Depending on the parameter that evaluates spin memory loss, spin-flip transfer and reflection are more or less likely to occur. Spin torque and spin memory loss are intricately linked. In the linear muffin-tin orbital technique, we use circuit theory to find and the Landauer-Büttiker method to find the spin-flip scattering rates for the interfaces N|N, F|N, and F|F.