Microstructural characterization of granular CuCo rapidly solidified ribbons

The microstructure and magnetic properties of granular CuCo alloys obtained by planar flow casting in controlled atmosphere have been characterised by transmission electron microscopy (TEM), small angle neutron scattering (SANS), and magnetisation measurements. The magnetoresistance measurements have been performed using the classical de four probe method. The influence of quenching rate on the structural and magnetic properties has been investigated. The TEM and SANS data indicate a marked change in the morphology for samples obtained with wheel velocities greater than 19 m/s, and in the same samples a significant decrease of the magnetic moment is observed. The as cast samples, as well as the ones subjected to isothermal annealing at 713 K or to Joule heating up 7 A, show little variation of their microstructure. Treatments with 10 A Joule currents induce the formation of well defined Co precipitates. The effect of cold lamination on the giant magnetoresistance properties has also been investigated.