Controlled phase shifts in interlayer magnetic coupling with the doping of the magnetic layer

Abstract
We report the first observation of a strong change in the phase (up to 360 degrees) of the interlayer magnetic exchange coupling in Co/Ru/Co and Co/Cu/Co trilayer system which is controlled by the addition of small amounts of Ag (up to 8%) to the Co layers. The phase shifts may be due to modifications of magnetic-film spin-dependent potentials which control conduction electron contributions to the interlayer coupling. In addition, a strong additive antiparallel bias to the interlayer magnetic exchange coupling in Co/Ru/Co trilayers is observed, indicating a possible additive superexchange interaction.