Superconductivity and ferromagnetism: mechanisms of interaction and coexistence in a two-band model

摘要

We consider the problem of the competition and coexistence of singlet superconductivity and itinerant ferromagnetism in a system where the two orders are confined in different layers. The consequences of the charge transfer and the spin exchange between the subsystems are investigated with the aim to extract the region of parameters where a coexistence state is allowed. The results are discussed in the context of layered materials where the coexisting superconductivity and ferromagnetism are due to different electrons, like in the rutheno-cuprate GdSr2Ru2Cu2O8 compound. An analysis of the case where non-uniform superconductivity may occur is also presented.