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Quadrupolar effect and rattling motion in heavy fermion superconductor PrOs_4Sb_{12}

Terutaka Goto·Yuichi Nemoto·Kazuhiro Sakai·Takashi Yamaguchi·Mitsuhiro Akatsu·Tatsuya Yanagisawa·Hirofumi Hazama·Kei Onuki·Hitoshi Sugawara·Hideyuki Sato
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Abstract

The elastic properties of a filled skutterudite PrOs_4Sb_{12} with a heavy Fermion superconductivity at T_C=1.85 K have been investigated. The elastic softening of (C_{11}-C_{12})/2 and C_{44} with lowering temperature down to T_C indicates that the quadrupolar fluctuation due to the CEF state plays a role for the Cooper paring in superconducting phase of PrOs_4Sb_{12}. A Debye-type dispersion in the elastic constants around 30 K revealed a thermally activated Gamma_{23} rattling due to the off-center Pr-atom motion obeying tau=tau_{0}exp(E/k_{B}T) with an attempt time tau_0=8.8*10^{-11} sec and an activation energy E=168 K. It is remarkable that the charge fluctuation of the off-center motion with Gamma_{23} symmetry may mix with the quadrupolar fluctuation and enhance the elastic softening of (C_{11}-C_{12})/2 just above T_C.

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Terutaka Goto, Yuichi Nemoto, Kazuhiro Sakai, Takashi Yamaguchi, Mitsuhiro Akatsu, Tatsuya Yanagisawa, Hirofumi Hazama, Kei Onuki, Hitoshi Sugawara, Hideyuki Sato. 2004-04-08. Quadrupolar effect and rattling motion in heavy fermion superconductor PrOs_4Sb_{12}. https://doi.org/10.1103/physrevb.69.180511

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