Effect of Interfacial Spin Flip and Momentum Scattering on Magnetoresistance

Abstract

In this paper, we have developed a model and performed a numerical analysis using the spin-drift diffusion method to study the effect of interfacial spin scattering on the magnetoresistance of a simple trilayer spin-valve structure. We have modelled the interfaces as ultra-thin layers, in the limit of the layer thickness approaching zero. Our analysis is focused on three important interfacial parameters, i.e., interfacial resistance (RI), interfacial spin selectivity (gamma), and interfacial spin-flip parameter (zeta). We compared the relative contribution of bulk scattering (BS) and interfacial scattering (IS) to the overall MR. We have noticed that when gamma is greater (smaller) than a critical value, gammaC, then MR increases with increasing (decreasing) RI. Contrary to general expectation, larger ferromagnetic (FM) resistivity results in lower MR if gamma>gammaC. Finally, we have shown the effect of zeta on MR. At high (low) zeta, which signifies spin coherence at the interface is conserved (depolarized), MR increases (decreases). We have also noted the competition between gamma and zeta in contributing towards overall MR. We have also shown that the negative effect on MR due to spin flip can be minimized by using higher RI