Abstract
The microscopic details of the suppression of antiferromagnetic order in the Kondo-lattice series Ce1−xLaxCu2Ge2 due to nonmagnetic dilution by La are revealed through neutron diffraction results for x=0.20, 0.40, 0.75, and 0.85. Magnetic Bragg peaks are found for 0.20≤x≤0.75, and both the Néel temperature TN and the ordered magnetic moment per Ce μ linearly decrease with increasing x. The reduction in μ points to strong hybridization of the increasingly diluted Ce 4f electrons, and we find a remarkable quadratic dependence of μ on the Kondo-coherence temperature. We discuss our results in terms of local-moment- versus itinerant-type magnetism and mean-field theory and show that Ce1−xLaxCu2Ge2 provides an exceptional opportunity to quantitatively study the multiple magnetic interactions in a Kondo lattice.
