Spin valves with synthetic ferrimagnet and antiferromagnet free and pinned layers

Spin valve structures with both synthetic ferrimagnet F_a/Re/F_b free layers and synthetic antiferromagnet F₁/Re/F₂/AF pinned layers are demonstrated. Physical thicknesses for the free layer of ≈50 Å can be maintained while decreasing the effective magnetic thickness (t_eff ) to 8-10 Å, without significant signal loss. Inverted structures with the synthetic free layer on top present magnetoresistance (MR) values up to 7% for t_eff~17 Å. The synthetic pinned layer gives high unidirectional exchange H_ex (~1250 Oe) and saturation fields H_s (~3-4 KOe) with no significant change after several hours anneal at 300°C. MR decreases linearly as the temperature increases ((1/MR(RT))x dMR(T)/dT≈-0.0017/°C)