Thermal stability of sputtered Ni81Fe19/Ag multilayers

From the observation of magnetic and structural properties of Ag/Ni81Fe19 multilayers, we show that two diffusion mechanisms are involved in the thermal evolution of such structures: the diffusion of Ag at interfaces and at grain boundaries. Upon annealing, they first lead to a decrease in interface roughness and then cause the layers to become discontinuous. We have also observed that thermal treatments under an applied magnetic field have an influence on the magnetoresistive properties of the samples. This could be due to some modification of the domain structure, resulting in a different contribution of electron scattering by domains walls.