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Novel Phase Transition Near the Quantum Critical Point in the Filled-Skutterudite Compound CeOs4Sb12: an Sb-NQR Study

Mamoru Yogi·Hisashi Kotegawa·Guo-qing Zheng·Yoshio Kitaoka·Shuji Ohsaki·Hitoshi Sugawara·Hideyuki Sato
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Abstract

We report on a novel phase transition at $T$ = 0.9 K in the Ce-based filled-skutterudite compound CeOs$_{4}$Sb$_{12}$ via measurements of the nuclear-spin lattice relaxation rate $1/T_{1}$ and nuclear quadrupole resonance (NQR) spectrum of Sb nuclei. The temperature ($T$) dependence of $1/T_1$ behaves as if approaching closely an antiferromagnetic (AFM) quantum critical point (QCP), following the relation $1/T_{1}\propto T/(T-T_{\rm N})^{1/2}$ with $T_{\rm N} = 0.06$ K in the range of $T=1.3-25$ K. The onset of either the spin-density-wave (SDW) or charge-density-wave (CDW) order at $T_{\rm 0} = 0.9$ K, that is, of the first order, is evidenced by a broadening of the NQR spectrum and a marked reduction in $1/T_1$ just below $T_{\rm 0}$. The $f$-electron-derived correlated band realized in CeOs$_{4}$Sb$_{12}$ is demonstrated to give rise to the novel phase transition on the verge of AFM QCP.

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Mamoru Yogi, Hisashi Kotegawa, Guo-qing Zheng, Yoshio Kitaoka, Shuji Ohsaki, Hitoshi Sugawara, Hideyuki Sato. 2005-07-20. Novel Phase Transition Near the Quantum Critical Point in the Filled-Skutterudite Compound CeOs4Sb12: an Sb-NQR Study. https://doi.org/10.1143/jpsj.74.1950

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