Interface proximity effects in current-perpendicular-to-plane magnetoresistance

Interface proximity effects in current-perpendicular-to-plane magnetoresistance" (2007). Using a tight-binding model that takes into account a realistic electronic band structure and includes defect scattering we investigate spin-dependent transport in Co/ Cu/ Co trilayers when current flows perpendicular to the plane. We show that resistance of the Co/ Cu interface depends on the proximity of another interface, which makes the parameters characterizing the spin-dependent interface resistance AR F/N * and ␥ F/N , to be dependent on the layer thickness separating the two interfaces. This leads to a decrease in the measurable quantity SR = ͱ͑AR AP ͒͑AR AP − AR P ͒ with the Cu layer thickness and, therefore, to the departure from the series-resistor model. Here AR AP is the specific resistance ͑area A times resistance R͒ of the trilayer when magnetizations of the two Co layers are aligned antiparallel ͑AP͒ to each other, and AR P is the specific resistance when the layer magnetizations are aligned parallel ͑P͒. We demonstrate that recent experimental data on current-perpendicular-to-plane transport in Co/ Cu/ Co spin valves can be explained by the interface proximity effects without introducing a finite spin-diffusion length.