Magneto-volume effects in some selected heavy-fermion compounds

We present a review of recent magneto-volume experiments, such as thermal expansion and magnetostriction, performed on good-quality single crystals of heavy-fermion systems, like CeCu6, CeRu2Si2, URu2Si2, UBe13 and UPt3. All investigated compounds exhibit large magneto-volume effects at low temperatures, as is reflected by their huge Grüneisen parameters (at least two orders of magnitude larger than in ordinary metals). A combination of specific-heat and thermal-expansion data yields furthermore information on the pressure dependence of the characteristic temperatures, and allows, in particular cases, for a detailed separation of the Kondo, crystal-field, phonon or other contributions to the thermal properties. We also discuss the magneto-volume effect connected with the metamagnetic-like transitions observed at 20 and 8 T (at 4.2K) for UPt3 and CeRu2Si2, respectively.