Strong coupling between 4f valence instability and 3d ferromagnetism in Yb(x)Fe4Sb12 studied by resonant x-ray emission spectroscopy

Hitoshi Yamaoka; Ignace Jarrige; Naohito Tsujii; Jung-Fu Lin; Tsuyoshi Ikeno; Yosikazu Isikawa; Katsuhiko Nishimura; Ryuji Higashinaka; Hideyuki Sato; Nozomu Hiraoka; Hirofumi Ishii; Ku-Ding Tsuei

doi:10.1103/PhysRevLett.107.177203

Strong coupling between 4f valence instability and 3d ferromagnetism in Yb(x)Fe4Sb12 studied by resonant x-ray emission spectroscopy

Phys Rev Lett. 2011 Oct 21;107(17):177203. doi: 10.1103/PhysRevLett.107.177203. Epub 2011 Oct 19.

Authors

Hitoshi Yamaoka¹, Ignace Jarrige, Naohito Tsujii, Jung-Fu Lin, Tsuyoshi Ikeno, Yosikazu Isikawa, Katsuhiko Nishimura, Ryuji Higashinaka, Hideyuki Sato, Nozomu Hiraoka, Hirofumi Ishii, Ku-Ding Tsuei

Affiliation

¹ Harima Institute, The Institute of Physical and Chemical Research (RIKEN), Sayo, Hyogo 679-5148, Japan.

PMID: 22107574
DOI: 10.1103/PhysRevLett.107.177203

Abstract

We have investigated the temperature and pressure dependency of the electronic structure of Yb-filled skutterudites, YbFe(4)Sb(12) and Yb(0.88)Fe(4)Sb(12), using x-ray absorption and emission spectroscopies. An anomalous increase of the Yb valence, which is beyond the conventional Anderson model picture, is found to coincide with the onset of the ferromagnetic order in the x=0.88 sample below 20 K. In contrast, the nearly stoichiometric YbFe(4)Sb(12) is paramagnetic down to 2 K and the Yb valence is independent of temperature. This evidences a close interplay between the magnetic instability of the Fe 3d electrons and valence instability of the Yb 4f electrons. Under pressure, a sudden increase in the valence is found to occur around 13 GPa for YbFe(4)Sb(12) and 17 GPa for Yb(0.88)YbFe(4)Sb(12).