[en] The lattice dynamics of the filled skutterudite YbFe4Sb12 was studied by resonant ultrasound spectroscopy and an anomalous softening in the temperature dependence of the elastic constants at similar to 50 K was observed. This anomaly can not be explained by the dynamics of the filler, in contrast to other filled skutterudites. We have further investigated the origin of this anomaly using macroscopic and microscopic measurements. A rearrangement of the spectral weight of the Yb phonon states was observed in the temperature dependence of the density of phonon states, obtained by inelastic neutron scattering. We suggest that the anomaly is due to a change of the Yb valence state and that the anomaly and the phonon spectral weight rearrangement have the same origin.
Disciplines :
Physics
Author, co-author :
Moechel, A.
Sergueev, I.
Wille, H.-C.
Voigt, J.
M., Prager
Stone, M. B.
Sales, B. C.
Guguchia, Z.
Shengelaya, A.
Keppens, V.
Hermann, Raphaël ; Université de Liège - ULiège > Département de chimie (sciences) > Département de chimie (sciences)
Language :
English
Title :
Lattice dynamics and anomalous softening in the YbFe4Sb12 skutterudite
Publication date :
2011
Journal title :
Physical Review
ISSN :
0031-899X
eISSN :
1536-6065
Publisher :
American Physical Society, Lancaster, United States - Pennsylvania