Compositional control of interlayer magnetic coupling in Co/Ru/Co(Ag) and Co/Cu/Cd(Ag) trilayer films

In this paper we report a large change in the phase (up to 360 degrees) of the interlayer magnetic exchange coupling in Co/Ru/Co and Co/Cu/Co trilayer systems which is controlled by the addition of small amounts of Ag, Au or Cu (up to 8%) to the Co layers. An analysis of the phase shifts is made in terms of charge transfer from the doping atoms which modifies the interfacial spin dependent potentials is discussed and found to be consistent with charge transfer based on band calculations for Ag doped Co. In addition, a strong antiparallel bias to the interlayer magnetic exchange coupling in Co/Ru/Co trilayers is observed for small spacer layer thicknesses, suggesting the existence of an additive superexchange interaction.