Chemical pressure effects on the Kondo behaviour of CePt₂Ge₂

Abstract

The compound, CePt₂Ge₂, recently reported to crystallize in a monoclinic modification of the CaBe₂Ge₂ structure, has been identified to be an antiferromagnetic Kondo lattice (T_N=2.2 K). The influence of positive and negative chemical pressure on the Kondo behavior is investigated by measurements of magnetic susceptibility and electrical resistivity (ρ) on the solid solutions, Ce_1-x La_x Pt₂Ge₂ and Ce_1-z Y_z Pt₂Ge₂. Y and La substituents cause nearly similar effects on the magnetic and electrical resistivity behaviour of CePt₂Ge₂, though the unit-cell volumes vary in opposite directions. We propose that the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction may contribute to decide the temperature at which ρ attains a maximum at low temperatures (~5 K) in CePt₂Ge₂.