SUPERCONDUCTING AND NORMAL PROPERTIES OF CECU2GE2 AT HIGH-PRESSURE

The electronic properties of CeCu2Ge2 have been investigated under pre ssure (P) up to 15 GPa by detailed resistivity versus temperature (50 mK < T < 300 K) measurements performed in the basal plane of the tetra gonal structure for different single crystals. With increasing P, the compound evolves from antiferromagnetically ordered Kondo to intermedi ate valence behaviour as the Kondo temperature increases by about two orders of magnitude. At low P, two magnetic ordering temperatures are observed. Magnetic ordering vanishes between 7 and 10 GPa, depending o n the sample, and in parallel, superconductivity appears at a critical temperature T-c similar to 0.6 K which remains nearly constant up to 13 GPa. At higher P. T-c increases rapidly, reaches almost 2 K for P s imilar to 16 GPa and then vanishes at P similar to 20 GPa. The T-c(P) maximum corresponds to the occurrence of a pronounced maximum of the r esidual resistivity. (C) 1998 Elsevier Science B.V. All rights reserve d.