Structural evolution of Co clusters on Cu90Co10 upon annealing

A granular alloy, composed of cobalt embedded in a copper matrix, was studied by using EXAFS and magnetotransport measurements as function of annealing parameters (temperature and annealing time). The results suggest that different annealing routes can reach the same final state. For annealing temperatures up to 450°C, the results indicate the coalescence of cobalt atoms, resulting in magnetic particles with increasing size. On the other hand, the annealing at 500°C shows a rapid formation of cobalt particles and then the re-dissolution of cobalt atoms in the copper matrix.