Impurity scattering from δ-layers in giant magnetoresistance systems -: art. no. 220405

The properties of the archetypal Co/Cu giant magnetoresistance (GMR) spin-valve structure have been modified by the insertion of very thin (submonolayer) delta -layers of various elements at different points within the Co layers, and at the Co/Cu interface. Different effects are observed depending on the nature of the impurity, its position within the periodic table, and its location within the spin valve. The GMR can be strongly enhanced or suppressed for various specific combinations of these parameters, giving insight into the microscopic mechanisms giving rise to the GMR. In particular, the doping of Fe and Ni into the spin valve close to, but not at the interface, leads to an increase in GMR, as does the introduction of Cu, a nonmagnetic impurity, into the Co layers.