Giant magnetoresistance in Co/Cu multilayers after annealing

Multilayer films of [Co 10 Å/Cu(t)]64 with copper thicknesses from t=10 to 29 Å annealed for 1 h at temperatures about 350°C showed a decrease in sample resistivity at 4.2 K. The giant magnetoresistance (GMR) maximums for as-deposited films at t=10 Å and t=23 Å shifted with annealing. The GMR decreased for t=10 Å and t=23 Å but increased for t=19 Å and t=29 Å indicating a complex behavior with annealing. Similarities with granular films are discussed.