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The microscopic details of the suppression of antiferromagnetic order in the Kondo-lattice series Ce_1-xLa_xCu₂Ge₂ 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 Neel temperature, T_N, 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 Ce_1-xLa_xCu₂Ge₂ provides an exceptional opportunity to quantitatively study competing magnetic interactions in a Kondo lattice.
arXiv:1710.08329