Anisotropic spin-dynamics in the Kondo semiconductor CeRu2Al10
  Spin dynamics in the new Kondo insulator compound CeRu2Al10 has been studied using unpolarized and polarized neutron scattering on single crystals. In the unconventional ordered phase forming below T0 = 27.3 K, two excitation branches are observed with significant intensities, the lower one of which has a gap of 4.8 +/- 0.3 meV and a pronounced dispersion up to about 8.5 meV. Comparison with RPA magnon calculations assuming crystal-field and anisotropic exchange couplings captures major aspects of the data, but leaves unexplained discrepancies, pointing to a key role of direction-specific hybridization between 4f and conduction band states in this compound. 
Julien Robert, Jean-Michel Mignot, Sylvain Petit, Paul Steffens,   Takashi Nishioka, Riki Kobayashi, Masahiro Matsumura, Hir...
cond-mat.str-el