Concentrated Kondo Systems in Solid Solutions on the Base of Europium Ternary Compounds

The experimental results of the components substitution effect on crystal structure, electronic transport properties, and Eu effective valence in solid solutions based on EuCu₂Si₂ and EuPd₂Si₂ ternary compounds are presented. It is shown, that when the Eu effective valence reaches the critical value v = 2.1, corresponding to degeneration of the 4f⁷ and 4f⁶ configurations, the condition of the concentrated Kondo system and an essential perturbation of the band electron spectrum near the Fermi level occur.