Enhancement of current-perpendicular-to-plane giant magnetoresistance in Heusler-alloy based pseudo spin valves by using a CuZn spacer layer

Enhancement of magnetoresistance output was attained in current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices by using a bcc CuZn alloy for the spacer. Pseudo spin valves that consisted of the Co2Fe(Ga0.5Ge0.5) Heusler alloy for ferromagnetic layers and CuZn alloy with the composition of Cu52.4Zn47.6 for a spacer showed the large change of the resistance-area products, ΔRA, up to 8 mΩ·μm2 for a low annealing temperature of 350 °C. The ΔRA value is one of the highest reported so far for the CPP-GMR devices for the low annealing temperature, which is essential for processing read heads for hard disk drives. We consider that the enhancement of ΔRA is produced from the spin-dependent resistance at the Co2Fe(Ga0.5Ge0.5)/CuZn interfaces.