Specific heat and magnetization studies of spin-glass like transition in nanogranular Cu90Co10 ribbon

Low temperature measurements of specific heat and magnetic properties were performed on granular Cu90Co10 ribbons prepared by melt spinning technique. The thermal and magnetic behavior of an as-quenched sample is compared to that of an annealed sample at 500 °C for 1 h. It was found that the electronic specific heat γ decreases about 50% and the magnetic properties change from spin-glass to superparamagnetic with the annealing process. These results are interpreted and discussed considering the role of isolated Co atoms in the RKKY interaction among small nanoparticles.