Electrical resistivity of the Kondo systems (Ce1−xLax)TSi3 (T=Rh, Ir)

The electrical resistivities of the pseudo-ternary alloys (Ce1−xLax)TSi3 (T=Rh, Ir; 0≤x≤1) are reported. The 4f-derived part of their resistivities, ρ4f, is found by subtracting the temperature-dependent part of the resistivity of LaTSi3. A maximum, characteristic of dense Kondo systems, is obtained in ρ4f at a temperature Tmax=105 K for CeRhSi3 and at 130 K for CeIrSi3. Tmax decreases for both compounds with increased La concentration, x. X-ray powder diffraction was used to measure the increase in tetragonal unit cell volume V for the (Ce1−xLax)TSi3 alloys with increase in x. The compressible Kondo model is applied to describe our results of Tmax(x) in terms of the on-site Kondo exchange interaction J and the electronic density of states N(EF) at the Fermi level. The experimental results yield |JN(EF)|x=0=0.072±0.016 for CeRhSi3 and 0.070±0.001 for CeIrSi3.