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Anomalous heavy-fermion and ordered states in the filled skutterudite PrFe4P12

Y. Aoki·T. Namiki·T. D. Matsuda·K. Abe·H. Sugawara·H. Sato
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Abstract

Specific heat and magnetization measurements have been performed on high-quality single crystals of filled-skutterudite PrFe_4P_{12} in order to study the high-field heavy-fermion state (HFS) and low-field ordered state (ODS). From a broad hump observed in C/T vs T in HFS for magnetic fields applied along the <100> direction, the Kondo temperature of ~ 9 K and the existence of ferromagnetic Pr-Pr interactions are deduced. The {141}-Pr nuclear Schottky contribution, which works as a highly-sensitive on-site probe for the Pr magnetic moment, sets an upper bound for the ordered moment as ~ 0.03 μ_B/Pr-ion. This fact strongly indicates that the primary order parameter in the ODS is nonmagnetic and most probably of quadrupolar origin, combined with other experimental facts. Significantly suppressed heavy-fermion behavior in the ODS suggests a possibility that the quadrupolar degrees of freedom is essential for the heavy quasiparticle band formation in the HFS. Possible crystalline-electric-field level schemes estimated from the anisotropy in the magnetization are consistent with this conjecture.

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Y. Aoki, T. Namiki, T. D. Matsuda, K. Abe, H. Sugawara, H. Sato. 2002-01-04. Anomalous heavy-fermion and ordered states in the filled skutterudite PrFe4P12. https://doi.org/10.1103/physrevb.65.064446

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