Abstract
The analysis of the antiferromagnetic (AFM) exchange coupling in epitaxial Co/Ru superlattices is reported. The AFM coupling oscillates as a function of Ru thickness with a period of approx 11 A for both perpendicular and in-plane easy magnetization axis, and depends significantly upon the cobalt sublayer thickness. For small Ru interlayer thickness, a large antiferromagnetic (AFM) exchange coupling between the Co sublayers is observed which influences strongly the magnetization process as the magnetization within Co sublayers can no longer be considered as fully locked ferromagnetically. In this condition, the magnetization process differs notably from the linear behaviour expected from simple models.