Magnetic-field-independent ultrasonic dispersions in the magnetically robust heavy fermion system SmOs4Sb12

Tatsuya Yanagisawa, Yoichi Ikeda, Hitoshi Saito, Hiroyuki Hidaka, Hiroshi Amitsuka, Koji Araki, Mitsuhiro Akatsu, Yuichi Nemoto, Terutaka Goto, Pei Chun Ho, Ryan E. Baumbach, M. Brian Maple

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13 Citations (Scopus)


Elastic properties of the filled skutterudite compound SmO s4Sb12 have been investigated by ultrasonic measurements. The elastic constant C11(ω) shows two ultrasonic dispersions at ∼15 and ∼53K for frequencies ω between 33 and 316 MHz, which follow a Debye-type formula with Arrhenius-type temperature-dependent relaxation times and remain unchanged even with applied magnetic fields up to 10 T. The corresponding activation energies were estimated to be E2 = 105K and E1 = 409 K, respectively. The latter, E1, is the highest value reported thus far in the Sb-based filled skutterudites. The presence of magnetically robust ultrasonic dispersions in SmOs4Sb12 implies a possibility that an emergence of a magnetically insensitive heavy fermion state in this system is associated with a novel local charge degree of freedom, which causes the ultrasonic dispersion.

Original languageEnglish
Article number043601
JournalJournal of the Physical Society of Japan
Issue number4
Publication statusPublished - 2011 Apr


  • Elastic constant
  • Filled skutterudite
  • Heavy fermion
  • Rattling
  • Ultrasonic dispersion


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