MR characteristics of synthetic ferrimagnet based spin-valves with different pinning layer thickness ratios

The dependence of magnetoresistance (MR) ratio and pinning characteristics on the two pinning layer thicknesses, in synthetic ferrimagnetic (SF) structure (P2/Ru/P1/AF), was investigated. The pinning field decreased monotonically when /spl Delta/t (=t/sub P2/-t/sub P1/)=0 while it has its maximum at a specific t/sub P2/ when /spl Delta/t(=t/sub P2/-t/sub P1/)/spl ne/0 as t/sub P2/ increased. MR ratio reached its maximum at a specific t/sub P2/ as t/sub P2/ increased. In the case of the fixed t/sub P2/, pinning field decreased whereas MR ratio increased as /spl Delta/t increased. This trend is also found when the total thickness of P1 and P2 is fixed so that the current shunting to synthetic ferrimagnet (SF) trilayer is fixed. Both strong pinning field and sufficient MR ratio could be obtained by selecting appropriate /spl Delta/t under the constraint of constant total thickness of SF trilayer.