Magnetic instabilities in CeRu2Si2 compounds

Neutron scattering experiments were recently performed in compounds of the CeRu2Si2 family. The topic addressed is the proximity of magnetic instabili ties. The first one is the proximity of a T = 0 K quantum phase transition experimentally achieved with lanthanum doping. The second kind of instabili ty is linked to the competition between antiferromagnetic and ferromagnetic interactions in these materials. The pseudo-metamagnetic transition of CeR u2Si2 and the occurrence of an antiferromagnetic phase in the ferromagnetic compound CeRu2Ge2 were studied. Comparisons with macroscopic measurements are made using a simple analysis of the data. (C) 1999 Elsevier Science B.V . All rights reserved.