Unusual Low Temperature Behavior in Diluted Kondo Lattice Compound Ce_1-x(La_0.63Y_0.37)_xRu₂Si₂, (x≥0.50)

Abstract

The measurement of magnetic susceptibility χ( T ), specific heat C ( T ), electrical resistivity ρ( T ) and high field magnetization M ( H ) have been performed on dilute Ce compounds Ce 1- x (La 0.63 Y 0.37 ) x Ru 2 Si 2 , in which the lattice parameters are made independent of x to avoid the chemical pressure effect. Non-Fermi-liquid like behavior characterized by nearly logarithmic divergence of χ( T ) down to ∼200 mK has been observed as x →1, which is quite unexpected for the Kondo temperature T K ∼24 K of CeRu 2 Si 2 . We show that the characteristic behavior of the experimental results is well reproduced by an impurity Kondo model with a wide distribution in T K (“Kondo disorder”). A simple model for the T K distribution is given. In the present dilute alloys, T K strongly depends on the local environment of nearest-neighbor distance.