Magnetic and magnetotransport properties in Joule-heated granular Cu95Co5 ribbons

Cu95Co5 alloys, consisting of Co nanoparticles, were obtained by subjecting rapidly quenched ribbons to suitable dc Joule-heating treatments (0 <= I <= 5.75 A for 60 s) in order to induce different degrees of Co precipitation with particles having different average size. The behaviour of the resistance versus applied field is influenced by the structural changes (Co cluster formation) that occur in the samples after different thermal treatments. The dependance of the electric and magnetic properties on microstructural configurations has been studied by measuring room-temperature hysteresis loops and GMR. By combining the GMR response with magnetization data, information on the magnetic correlation between magnetic moments of neighbouring Co particles will be obtained and correlated to the different microstructures induced by current annealing. (C) 2006 Elsevier B.V. All rights reserved.