Oscillatory exchange coupling in the two-dimensional limit

The dimensionality aspects of the order–disorder transition in single and double magnetic layers is addressed. A single Fe film of three monolayers, embedded in V(001) layers, was determined to be two-dimensional and XY-like. Two Fe layers, separated by 14.4 monolayers of V(001), were determined to belong to the same universality class as the single Fe film. The interlayer exchange coupling was altered in situ by introducing hydrogen in the V layers. An oscillation of the ordering temperature was observed, consistent with an oscillatory interlayer exchange coupling. The two-dimensional nature of the bilayer was confirmed by the ratio of the interlayer and intralayer couplings ( ). The results therefore support the existence of an oscillatory exchange coupling in the quasi-two-dimensional limit.