Transition from dense Kondo to the intermediate-valence regime in the Ce (Pt1-xNix)2Si2 alloys

Abstract

Electrical resistivity ρ(T) measurements on polycrystalline samples of the Ce (Pt1−xNix)2Si2 system exhibit dense Kondo behaviour for alloys with . The temperature at which a maximum appears in ρ(T) shifts from Tmax = 65 K for x = 0 to Tmax = 290 K for x = 0.6 as the system evolves towards the intermediate-valence regime for the CeNi2Si2 compound. At low temperatures the Ce (Pt1−xNix)2Si2 alloys show a Fermi liquid T2 contribution to ρ(T) below the coherence temperature Tcoh. It is observed that , with a transition that takes place from a dense Kondo regime of TK< TCF () to a regime of TK> TCF (). TK () and TCF denote the Kondo and crystalline electric field splitting, EF and ER are the Fermi and the Abrikosov–Suhl resonance energies and j denotes the total angular momentum. An electronic Grüneisen parameter value of 19 has been obtained for the alloy system which is in reasonable agreement with Ω = 28 found from pressure studies on CePt2Si2. It is argued that volume effects are mainly responsible for the hybridization in the Ce (Pt1−xNix)2Si2 system and application of the compressible Kondo lattice model to Tmax data yields |JN(EF)| = 0.309 ± 0.008, where J is the on-site exchange interaction between conduction electrons and the localized 4f spin and N(EF) is the density of states at EF.

https://iopscience.iop.org/article/10.1088/0953-8984/16/15/016