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

The properties of the archetypal Co/Cu giant magnetoresistance (GMR) spin-v alve structure have been modified by the insertion of very thin (submonolay er) delta -layers of various elements at different points within the Co lay ers, and at the Co/Cu interface. Different effects are observed depending o n the nature of the impurity, its position within the periodic table, and i ts location within the spin valve. The GMR can be strongly enhanced or supp ressed for various specific combinations of these parameters, giving insigh t into the microscopic mechanisms giving rise to the GMR. In particular, th e doping of Fe and Ni into the spin valve close to, but not at the interfac e, leads to an increase in GMR, as does the introduction of Cu, a nonmagnet ic impurity, into the Co layers.