GIANT MAGNETORESISTANCE IN JOULE HEATED CU-CO RIBBONS

The evolution of negative giant magnetoresistance (GMR) is studied in two melt-spun Cu90Co10 ribbons produced with different quenching rates and submitted to different current annealings. The GMR depends on the heating parameters, displaying a maximum (similar to 7% at room tempe rature with a maximum field of 2 T) as a function of the electrical cu rrent (for fixed times of 60 s). The field behaviour of the resistance is influenced by the structural changes (Co cluster formation and gro wth) occurring in the samples because of the thermal treatments.