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arXiv · 0905.4591

Kondo-Cluster-Glass State near a Ferromagnetic Quantum Phase Transition

T. Westerkamp·M. Deppe·R. Kuechler·M. Brando·C. Geibel·P. Gegenwart·A. P. Pikul·F. Steglich
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Abstract

We report on a comprehensive study of CePd$_{1-x}$Rh$_x$ $(0.6 \leq x \leq 0.95)$ poly- and single crystals close to the ferromagnetic instability by means of low-temperature ac susceptibility, magnetization and volume thermal expansion. The signature of ferromagnetism in this heavy-fermion system can be traced from 6.6 K in CePd down to 25 mK for $x=0.87$. Despite pronounced non-Fermi-liquid (NFL) effects in both, specific heat and thermal expansion, the Gr\"uneisen ratio {\it does not} diverge as $T\to 0$, providing evidence for the absence of a quantum critical point. Instead, a peculiar "Kondo-cluster-glass" state is found for $x\geq 0.65$, and the NFL effects in the specific heat, ac susceptibility and magnetization are compatible with the quantum Griffiths phase scenario.

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T. Westerkamp, M. Deppe, R. Kuechler, M. Brando, C. Geibel, P. Gegenwart, A. P. Pikul, F. Steglich. 2009-05-28. Kondo-Cluster-Glass State near a Ferromagnetic Quantum Phase Transition. https://doi.org/10.1103/physrevlett.102.206404

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