Magnetism and superconductivity in heavy fermion systems

We discuss some consequences of the interplay between magnetism and superconductivity in the two heavy fermion systems URu₂Si₂ and UPt₃, notably on the temperature dependence of the specific heat, on possible observation of Larkin-OvchinnikovFulde-Ferrel phase, and on the anisotropy of the upper critical field. We demonstrate that in UPt₃, a clear double steep superconducting transition can be obtained reversibly.