Magnetic and magnetoresistance properties of synthetic spin valves with different pinning layer thicknesses

The effect of the pruning-layer thickness difference, Δt(= t_P2 - t_P1) in a synthetic ferrimagnetic (SAF) structure (P2/Ru/P1/AF) on the magnetoresistance (MR) behavior and the magnetic properties of a synthetic spin valve was investigated. In the samples with Δt < 0, inverse MR curves were observed because the direction of the pinning layer (P1) was opposite to that of the samples with Δt > 0. In the case of the spin valves (SVs) with Δt ≥ 0, the MR ratio increased with increasing Δt, but the effective exchange coupling strength field (H_eex) is decreased because a larger torque was exerted on the larger net magnetization. The magnitude and the position of the sub-peaks observed in SAF SVs were also very sensitively affected by Δt.