MU-SR STUDY OF THE MAGNETIC-ORDERING IN CE1-XLAXRU2SI2

Zero-field mu SR measurements have been carried out in the paramagneti c and magnetically ordered states of the heavy fermion alloys: Ce1-xLa xRu2Si2 (x = 0.05, 0.13, 0.25). In Ce1-xLaxRu2Si2 system, T-K drastica lly decreases with x from 24 K for x = 0 and becomes very close to the magnetic ordering temperature T-N. As functions of T-K and T-N, the m agnetic instabilities were studied in this system. For x = 0.05, 0.13 and 0.25 samples, longitudinal muon spin relaxation was measured to st udy non-magnetic to magnetic transition and the change from itinerant to localized electron state with increasing La impurities. We discuss the dynamics of muon spins in the paramagnetic and antiferromagnetic s tate.