Analysis on giant magnetoresistive characteristics of synthetic antiferromagnet-based spin valves with modified pinned layers

A parametric sensitivity analysis has been performed on a new type of synthetic antiferromagnet-based spin valves (SSVs) comprising a modified pinned structure using CoFe (P1)-Ru-CoFe (P2)-Ru-CoFe (P3). Recently, it was demonstrated that this type of modified synthetic spin valves (MSSVs) could deliver larger effective exchange field (H/sub ex.eff/) as well as better bias point control capability over a conventional SSV, in particular, when the device size became as small as 50 nm . A series of calculations based on the Landau-Lifschitz-Gilbert equation incorporating a single-domain multilayer model was carried out. We considered three key parameters such as an indirect exchange coupling energy (J/sub 1/) between P1-P2 as well as P2-P3, an exchange biasing energy between P1 and antiferromagnetic layer (J/sub eb/), and a relative giant magnetoresistive contribution (R) due to the angular difference of magnetizations in the pinned structure. It was found that J/sub 1/ was mainly related with the saturation field (H/sub s/) and the field at which the maximum subpeak magnetoresistance (MR) ratio (H/sub sub/) occurred, while J/sub eb/ influenced on the H/sub ex.eff/. R raised the MR ratio between the main peak and subpeak. As J/sub 1/ increased, H/sub ex.eff/ also increased. As the cell dimension decreased below 1 /spl mu/m, H/sub ex.eff/ and H/sub s/ increased while H/sub sub/ decreased rapidly.