Antiferromagnetism in CeAu2Si2- and CeAg2Si2-based Kondo-lattice systems

Abstract

We report the electrical resistivity rho , thermopower S and thermal conductivity lambda of Ce1-xLaxAu2Si2, Ce1-yYyAu2Si2, Ce1-xLaxAg2Si2 and Ce1-yYyAg2Si2 (0<or=x, y<or=1) systems. The rho curves show a sudden change in slope at the antiferromagnetic ordering temperature TNrho . In the CeAu2Si2-based alloys, the TN depression, due to the dilution of Ce atoms by La or Y, is accounted for solely by the weakening of the inter-site interaction temperature scale TRKKY. On the other hand, in the CeAg2Si2-based alloys, apart from TRKKY, the single-ion Kondo temperature TK also plays an important role in determining the nature of the TN variation. The rho and lambda behaviours, at both low and high temperatures, show clear evidence for the Kondo effect in the presence of crystal fields.