Reduction of the ordered-magnetic moment and its relationship to Kondo coherence in Ce${}_{1-x}$La${}_x$Cu${}_2$Ge${}_2$

Abstract

The microscopic details of the suppression of antiferromagnetic order in the Kondo-lattice series Ce${}_{1-x}$La${}_x$Cu${}_2$Ge${}_2$ 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 $0.20\le x\le 0.75$, and both the Néel temperature, $T_{\text{N}}$, and the ordered magnetic moment per Ce, $\mu$, linearly decrease with increasing $x$. The reduction in $\mu$ points to strong hybridization of the increasingly diluted Ce $4f$ electrons, and we find a remarkable quadratic dependence of $\mu$ 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${}_{1-x}$La${}_x$Cu${}_2$Ge${}_2$ provides an exceptional opportunity to quantitatively study competing magnetic interactions in a Kondo lattice.

arXiv commentSupplementary material included

References in corpus (5)

• Onset of antiferromagnetism in heavy fermion metals
• Quantum phase transitions in heavy fermion metals and Kondo insulators
• Simple cubic random-site percolation thresholds for complex neighbourhoods
• Field-induced quantum fluctuations in the heavy fermion superconductor CeCu2Ge2
• Remarkably robust and correlated coherence and antiferromagnetism in (Ce${}_{1-x}$La${}_x$)Cu${}_2$Ge${}_2$

Cited by in corpus (4)

• Percolation thresholds on triangular lattice for neighbourhoods containing sites up-to the fifth coordination zone
• Site percolation thresholds on triangular lattice with complex neighborhoods
• Universality of random-site percolation thresholds for two-dimensional complex non-compact neighborhoods
• Lower limit of percolation threshold on a square lattice with complex neighborhoods