Theoretical modeling of half-metallic current-perpendicular-to-plane spin valves

Abstract

We conducted theoretical studies of the magnetoresistance (MR) behavior of the current-perpendicular-to-plane spin valves (SVs) with half-metallic (HM) layers replacing either the pinned layer or both the pinned and the free ferromagnetic (FM) layers. In the single HM layer SV, resistance matching between the HM and the FM layers is important in order to avoid the decrease in MR due to the dominance of the single FM layer with respect to the resistance. For the dual HM layer SV, the presence of the HM layers results in a plateau of high MR values over a wider range of HM resistivity. As expected, the MR ratio is suppressed in the low HM resistivity range because of low spin-dependent scattering. Unexpectedly, the MR also reduces to zero at extremely high HM resistivity due to the effect of spin flipping.