Crystal-field excitations inCeB6studied by Raman and neutron spectroscopy

The ${\Gamma }_8-{\Gamma }_7$ crystalline-electric-field (CEF) transition of ${\mathrm{CeB}}_6$ has been identified near 530 K (46 meV, 372 ${\mathrm{cm}}^{-1\mathrm{}}$) with use of inelastic neutron and polarized Raman scattering. From the anomalous temperature behavior of the transition energy observed in Raman scattering we deduce a ${\Gamma }_8$ ground state split by 20 ${\mathrm{cm}}^{-1\mathrm{}}$ (30 K). The novel CEF level scheme yields a consistent and unified interpretation of so far seemingly unrelated thermal, elastic, and magnetic data.