Spin-valve-like properties and annealing effect in ferromagnetic tunnel junctions

We fabricated ferromagnetic tunnel junctions with naturally oxidized Al barriers, and investigated the effects of Al oxidization time, Al thickness and annealing temperature on the tunnel properties. Changes of between 10 and 15% have been observed in the resistance, and in some junctions, the MR ratios increase by annealing at 250 to 300/spl deg/C. The Ni-Fe/Co/Al-AlO/sub x//Co/Ni-Fe/Fe-Mn/NiFe junction showed a 24% spin-valve-like MR change after annealing at 300/spl deg/C for one hour.