Effects of Ta seed layer and annealing on magnetoresistance in CoFePd -based pseudo-spin-valves with perpendicular anisotropy

We have studied the switching characteristics and magnetoresistance of pseudo-spin-valves with perpendicular anisotropy based on CoFePd multilayers. In unpatterned thin films without exchange biasing, a maximum current-in-plane giant magnetoresistance of 7% was achieved, the highest reported to date in perpendicular pseudo-spin-valves. A Ta seed layer and the fcc (111) orientation of Pd was shown to be important in order to achieve good perpendicular anisotropy and sharp switching behavior. The improvement in perpendicular anisotropy and decay in magnetoresistance upon postdeposition annealing have been attributed to the formation of CoPd alloys at the CoFePd interfaces.