Magnetoelastic excitation spectrum in the rare-earth pyrochlore Tb2Ti2O7

Amongst the rare earth pyrochlores, Tb${}₂$Ti${}₂$O${}₇$ remains mysterious: no theory of purely magnetic degrees of freedom can account entirely for its behavior. The discovery of a hybrid magnetoelastic excitation, formed from crystal field and phonon excitations, suggests that spin-lattice coupling may play an important role. Here, the authors use inelastic neutron scattering to make a detailed investigation of the hybrid mode and crystal field excitons that may hold the key to understanding the microscopic interactions of Tb${}₂$Ti${}₂$O${}₇$.