Dilution and non-Fermi-liquid effects in the CePtIn Kondo lattice

Abstract

Measurements of electrical resistivity (ρ(T)), magnetoresistivity (MR), magnetic susceptibility (χ(T)) and heat capacity (C(P)(T)) are presented for the (Ce(1-x)La(x))PtIn alloy system of which the CePtIn parent is a known dense Kondo compound that does not order magnetically down to 50 mK. χ(T) for alloys 0≤x≤0.8 exhibits Curie-Weiss behaviour. ρ(T) results indicate a transition from a dense Kondo behaviour for 0≤x≤0.2 to a single-ion Kondo region (0.3≤x≤0.8). The Kondo energy scale as given by T(K) values calculated from MR studies and by the temperature T(max)(ρ(mag)) where the magnetic contribution to ρ(T) exhibits a maximum value, is compared with theoretical models. It is shown that the experimental results not only depend on a volume effect as given by the compressible Kondo lattice model of Lavagna but in addition confirm the more complex behaviour recently presented by Burdin and Fulde for a Kondo alloy system in which the magnetic (Ce) and non-magnetic (La) atoms are distributed randomly. Non-Fermi-liquid behaviour is predicted by Burdin and Fulde at certain critical concentrations of the alloy system and experimental evidence for this is presented through χ(T), ρ(T) and C(P)(T) measurements.

Electronic Structure of CePtIn and LaPtIn Compounds

“…The specic heat and electrical resistivity studies indicate the absence of magnetic order up to 50 mK [3]. Temperature dependence of the electrical resistivity of LaPtIn indicates the metallic character and results for (Ce 1−x La x )PtIn system indicate its change of the properties with increasing La content [4].…”

Electronic Structure and Optical Properties of Ce1-xLaxPtIn (0<x<1) Compounds by SPR-KKR-CPA and FPLO-CPA Methods

“…It seems that the substitution Ce by La atoms can give new interesting physical results. Experimentally, such systems were studied by Ragel et al [7]. In order to calculate the change of the densities of states versus concentration we have applied the CPA.…”

“…We used two different methods: FPLO-CPA and SPR-KKR-CPA. The change of the lattice parameters with the concentration was assumed according to the experimental data [7]. The values of lattice parameters a and c increased linearly with the concentration x (Fig.…”

“…The physical properties of Ce(La)TIn (T = Pt, Pd) compounds were investigated experimentally and theoretically in the last years [1][2][3][4][5][6][7][8][9][10]. CePtIn is classified as the Kondo materials with the heat capacity C p /T about 1000 mJ K −2 mol −1 at low temperature [10].…”

“…The interesting physical problem is also the change of the electronic structure during the hydrogenation of LaPtIn and CePtIn [9]. The measurements of the electrical resistivity, magnetoresistivity and heat capacity by Ragel et al [7] indicated that the physical properties of Ce 1−x La x PtIn systems changed with the increase of La concentration. The photoemission measurements [8] have shown that the valence band in CePtIn and LaPtIn compounds was formed mainly by Pt 5d and In 5s and 5p states.…”