Composition and Temperature Dependence of Giant Magnetoresistance in Melt-Spun Co_{x}Cu_{100-x} Ribbons

Structure, magnetic properties and magnetoresistance in as-quenched and annealed Co$\text{}_{x}$Cu$\text{}_{100-x}$ samples were investigated. Homogeneous metastable Co$\text{}_{x}$Cu$\text{}_{100-x}$ alloys were prepared by the single-roller technique. The maximum value of magnetoresistance is shifted to higher annealing temperatures with increasing measuring temperature. At higher measuring temperatures the magnetoresistance is not saturated in fields as high as 16 T. Susceptibility measurements showed the formation of hcp-structured Co clusters. For small cobalt concentrations there is a transition from giant magnetoresistance to the normal anisotropic magnetoresistance.