Neutron diffraction and inelastic neutron scattering in the magnetodielectric regime of Ce₂O₃

The metastable material Ce₂O₃ has drawn recent attention due to reports of a giant magnetodielectric response of unknown origin, below a putative antiferromagnetic transition at T_N=6.2K. In the same temperature region, Raman spectroscopy has revealed the emergence of vibronic modes, which represent a relatively uncommon mixing of phonon and crystal field excitations.

Following up on these observations, we have performed a series of both neutron diffraction and inelastic scattering measurements on powders of Ce₂O₃. Our diffraction data allow us to comment on both the nature of the magnetically ordered state at low temperatures, and the variation in atomic structure as the material is varied through T_N. Our inelastic measurements focus on the temperature dependence of crystal field and phonon excitations at the energies of reported vibronic modes. I will present these data in the context of existing literature, and give our conclusions about the nature of the AF ground state and spin-lattice coupling in this material.