  The study of competing ground states is a central issue in condensed matter
physic. In this article we will discuss the interplay of antiferromagnetic
order and unconventional superconductivity in Ce based heavy-fermion compounds.
In all discussed examples superconductivity appears at the border of magnetic
order. Special focus is given on the pressure-temperature-magnetic field phase
diagram of CeRhIn5 and CeCoIn5 which allows to discuss microscopic coexistence
of magnetic order and superconductivity in detail. A striking point is the
similarity of the phase diagram of different classes of strongly correlated
systems which is discussed briefly. The recently discovered non-centrosymmetric
superconductors will open a new access with the possible mixing of odd and even
parity pairing.

Strongly Correlated Electrons