On the indirect exchange interaction in terms of an exactly soluble model

Abstract

An exactly soluble model is formulated for the case of two localized magnetic moments with spin S = 1 2 in ferro- or antiferromagnetic s-f ors-d interaction with a conduction-electron gas. This indirect exchange interaction model shows important differences between a ferro- and antiferromagnetic s-f interaction, e.g. in case of an antiferromagnetic s-f interaction both magnetic moments are never coupled in a purely ferromagnetic way. The model also exhibits the feature that in case the distance between both moments satisfies a special condition the correlation between these moments disappears, i.e. the indirect exchange interaction equals zero for these distances.