Superconductivity is one of the most fascinating phenomenon in solid state
physics. In a conventional superconductor Cooper-pairing is mediated by
phonons and strongly suppressed by the application of a magnetic field.
However, in heavy fermion systems superconductivity develops in close proximity
to magnetism or even coexists with magnetism. This opens the intriguing
question, which underlying mechanisms mediate superconductivity and/or lead to
magnetic order in this class of materials.
Superconductivity in heavy fermion compounds was first discovered 25 years ago
in CeCu2Si2 by Steglich et al.. Until recently, superconductivity in heavy
fermion systems appeared only at low temperatures bellow 1 K. CeCoIn5 a
member of the CeMIn5 (M=Co,Rh,Ir) family, enters the superconducting state
already at Tc=2.3 K, with a maximum Tc=2.6 K at an applied pressure of 1.6
GPa. CeCoIn5 is discussed as a promising candidate of a material where a
Fulde-Ferrel-Larkin-Ovchinnikov state is realized in the superconducting phase
at high magnetic fields. Another recently discovered system is CePt3Si.
CePt3Si is the first heavy fermion superconductor with a crystal structure
without centre of inversion. At ambient pressure CePt3Si orders
antiferromagnetically at TN=2.2 K and superconductivity develops in the
magnetic phase bellow Tc=0.75 K.
We present studies of transport and thermodynamic properties of CeMIn5
(M=Co,Rh,Ir) and CePt3Si under hydrostatic pressure and in magnetic fields.