Properties of Ferromagnetic Superconductors

Thanks to the discovery in the last decade of three uranium ferromagnetic superconductors, UGe2, URhGe and UCoGe, the fascinating aspects of the interplay between the triplet state of Cooper pairing and ferromagnetism have emerged. Furthermore, as the ferromagnetic properties in the normal state are quite different with respect to the proximity of the ferromagnetic-paramagnetic instabilities, the feedback with the coexistence of superconductivity gives rise to quite different boundaries in pressure and magnetic field. Special attention is given on the location of the materials with respect to the tricriticality and on the reinforcement of superconductivity in a transverse field response with respect to the direction of the ferromagnetic sublattice magnetization. The other facts of the interplay between ferromagnetism and superconductivity is briefly mentioned.