Transport and structure of Co10Cu90 heterogeneous ribbons during annealing

The resistivity of granular ribbons of composition Co10Cu90 was measured during annealing with different heating rates in order to follow the kinetics of the transformation of the original samples into the final aggregate with Co cluster distribution displaying giant magnetoresistance (GMR). These anneals show a clear two step process. associated to spinodal decomposition followed by nucleation and growth of Cc or Cp-rich grains. The hysteresis curves and magnetoresistance for these samples. measured at room temperature, show a clear change in size of the magnetic grains. The dependence of the magnetoresistance on the magnetization is investigated using a model developed by taking explicitly into consideration the magnetic moment distribution and the spin-dependent scattering both at interfaces and within the grains. (C) 1998 Elsevier Science B.V. All rights reserved.