Possibility of the Kondo effect in diluted EuPd2Si2 systems with constant lattice volume

Specific heat C and electrical resistivity ρ between 0.2 and 300 K were investigated for Eu-diluted alloys replacing by the (La0.67Y0.33) component with almost constant lattice volume, on a well-known valence-transition (VT) material EuPd2Si2. The inter-site cooperative effect bringing the sharp VT at 150 K in EuPd2Si2 was revealed to be disintegrated by the dilution beyond 25 at% for Eu from the present results in both the quantities. Moreover, a logarithmic upturn in ρ below about 20 K was recognized for the samples with the dilution beyond 25 at%, correspondingly with the steep enhancement in the magnetic part of C/T reaching 500 mJ/K2 Eu-mol toward the zero temperature. Discussion from the standpoint of the Kondo effect is briefly developed for the present Eu-diluted alloys