Abstract
The heavy-fermion intermetallic compound has been studied by means of inelastic neutron scattering. In agreement with a previous study, there is clear evidence from both the excitation energies and relative intensities that the crystal-electric-field ground state is the nonmagnetic, non-Kramers doublet, and this, together with enhanced thermodynamic properties at low temperatures, indicates that is a candidate quadrupolar Kondo material. In addition to the and excitations, which are seen at low temperature, we have observed the other two allowed transitions, and which are visible when the triplet becomes thermally populated. Within the Lea-Leask-Wolf parametrization scheme, we obtain and values that are similar to but slightly different from those previously reported. No magnetic quasielastic scattering is seen, down to ∼90 μeV, and this provides further evidence that the heavy-fermion behavior is unconventional and has a nonmagnetic origin. However, both the and levels are broadened significantly and to differing degrees. Possible sources of this broadening are discussed.
- Received 10 May 1999
DOI:https://doi.org/10.1103/PhysRevB.61.1831
©2000 American Physical Society